I am guessing the three tables you refer to are "orders", "orders_products" and "products".
This is what they look like:
CREATE TABLE IF NOT EXISTS orders (
orders_id int(11) NOT NULL auto_increment,
customers_id int(11) NOT NULL default '0',
customers_name varchar(64) collate latin1_general_ci NOT NULL default '',
customers_company varchar(64) collate latin1_general_ci default NULL,
customers_street_address varchar(64) collate latin1_general_ci NOT NULL default '',
customers_suburb varchar(32) collate latin1_general_ci default NULL,
customers_city varchar(32) collate latin1_general_ci NOT NULL default '',
customers_postcode varchar(10) collate latin1_general_ci NOT NULL default '',
customers_state varchar(32) collate latin1_general_ci default NULL,
customers_country varchar(32) collate latin1_general_ci NOT NULL default '',
customers_telephone varchar(32) collate latin1_general_ci NOT NULL default '',
customers_email_address varchar(96) collate latin1_general_ci NOT NULL default '',
customers_address_format_id int(5) NOT NULL default '0',
delivery_name varchar(64) collate latin1_general_ci NOT NULL default '',
delivery_company varchar(64) collate latin1_general_ci default NULL,
delivery_street_address varchar(64) collate latin1_general_ci NOT NULL default '',
delivery_suburb varchar(32) collate latin1_general_ci default NULL,
delivery_city varchar(32) collate latin1_general_ci NOT NULL default '',
delivery_postcode varchar(10) collate latin1_general_ci NOT NULL default '',
delivery_state varchar(32) collate latin1_general_ci default NULL,
delivery_country varchar(32) collate latin1_general_ci NOT NULL default '',
delivery_address_format_id int(5) NOT NULL default '0',
billing_name varchar(64) collate latin1_general_ci NOT NULL default '',
billing_company varchar(64) collate latin1_general_ci default NULL,
billing_street_address varchar(64) collate latin1_general_ci NOT NULL default '',
billing_suburb varchar(32) collate latin1_general_ci default NULL,
billing_city varchar(32) collate latin1_general_ci NOT NULL default '',
billing_postcode varchar(10) collate latin1_general_ci NOT NULL default '',
billing_state varchar(32) collate latin1_general_ci default NULL,
billing_country varchar(32) collate latin1_general_ci NOT NULL default '',
billing_address_format_id int(5) NOT NULL default '0',
payment_method varchar(128) collate latin1_general_ci NOT NULL default '',
payment_module_code varchar(32) collate latin1_general_ci NOT NULL default '',
shipping_method varchar(128) collate latin1_general_ci NOT NULL default '',
shipping_module_code varchar(32) collate latin1_general_ci NOT NULL default '',
coupon_code varchar(32) collate latin1_general_ci NOT NULL default '',
cc_type varchar(20) collate latin1_general_ci default NULL,
cc_owner varchar(64) collate latin1_general_ci default NULL,
cc_number varchar(32) collate latin1_general_ci default NULL,
cc_expires varchar(4) collate latin1_general_ci default NULL,
cc_cvv blob,
last_modified datetime default NULL,
date_purchased datetime default NULL,
orders_status int(5) NOT NULL default '0',
orders_date_finished datetime default NULL,
currency char(3) collate latin1_general_ci default NULL,
currency_value decimal(14,6) default NULL,
order_total decimal(14,2) default NULL,
order_tax decimal(14,2) default NULL,
paypal_ipn_id int(11) NOT NULL default '0',
ip_address varchar(96) collate latin1_general_ci NOT NULL default '',
PRIMARY KEY (orders_id),
KEY idx_status_orders_cust_zen (orders_status,orders_id,customers_id),
KEY idx_date_purchased_zen (date_purchased),
KEY idx_cust_id_orders_id_zen (customers_id,orders_id)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=3 ;
CREATE TABLE IF NOT EXISTS orders_products (
orders_products_id int(11) NOT NULL auto_increment,
orders_id int(11) NOT NULL default '0',
products_id int(11) NOT NULL default '0',
products_model varchar(32) collate latin1_general_ci default NULL,
products_name varchar(64) collate latin1_general_ci NOT NULL default '',
products_price decimal(15,4) NOT NULL default '0.0000',
final_price decimal(15,4) NOT NULL default '0.0000',
products_tax decimal(7,4) NOT NULL default '0.0000',
products_quantity float NOT NULL default '0',
onetime_charges decimal(15,4) NOT NULL default '0.0000',
products_priced_by_attribute tinyint(1) NOT NULL default '0',
product_is_free tinyint(1) NOT NULL default '0',
products_discount_type tinyint(1) NOT NULL default '0',
products_discount_type_from tinyint(1) NOT NULL default '0',
products_prid tinytext collate latin1_general_ci NOT NULL,
PRIMARY KEY (orders_products_id),
KEY idx_orders_id_prod_id_zen (orders_id,products_id),
KEY idx_prod_id_orders_id_zen (products_id,orders_id)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=3 ;
CREATE TABLE IF NOT EXISTS products (
products_id int(11) NOT NULL auto_increment,
products_type int(11) NOT NULL default '1',
products_quantity float NOT NULL default '0',
products_model varchar(32) collate latin1_general_ci default NULL,
products_image varchar(64) collate latin1_general_ci default NULL,
products_price decimal(15,4) NOT NULL default '0.0000',
products_virtual tinyint(1) NOT NULL default '0',
products_date_added datetime NOT NULL default '0001-01-01 00:00:00',
products_last_modified datetime default NULL,
products_date_available datetime default NULL,
products_weight float NOT NULL default '0',
products_status tinyint(1) NOT NULL default '0',
products_tax_class_id int(11) NOT NULL default '0',
manufacturers_id int(11) default NULL,
products_ordered float NOT NULL default '0',
products_quantity_order_min float NOT NULL default '1',
products_quantity_order_units float NOT NULL default '1',
products_priced_by_attribute tinyint(1) NOT NULL default '0',
product_is_free tinyint(1) NOT NULL default '0',
product_is_call tinyint(1) NOT NULL default '0',
products_quantity_mixed tinyint(1) NOT NULL default '0',
product_is_always_free_shipping tinyint(1) NOT NULL default '0',
products_qty_box_status tinyint(1) NOT NULL default '1',
products_quantity_order_max float NOT NULL default '0',
products_sort_order int(11) NOT NULL default '0',
products_discount_type tinyint(1) NOT NULL default '0',
products_discount_type_from tinyint(1) NOT NULL default '0',
products_price_sorter decimal(15,4) NOT NULL default '0.0000',
master_categories_id int(11) NOT NULL default '0',
products_mixed_discount_quantity tinyint(1) NOT NULL default '1',
metatags_title_status tinyint(1) NOT NULL default '0',
metatags_products_name_status tinyint(1) NOT NULL default '0',
metatags_model_status tinyint(1) NOT NULL default '0',
metatags_price_status tinyint(1) NOT NULL default '0',
metatags_title_tagline_status tinyint(1) NOT NULL default '0',
PRIMARY KEY (products_id),
KEY idx_products_date_added_zen (products_date_added),
KEY idx_products_status_zen (products_status),
KEY idx_products_date_available_zen (products_date_available),
KEY idx_products_ordered_zen (products_ordered),
KEY idx_products_model_zen (products_model),
KEY idx_products_price_sorter_zen (products_price_sorter),
KEY idx_master_categories_id_zen (master_categories_id),
KEY idx_products_sort_order_zen (products_sort_order),
KEY idx_manufacturers_id_zen (manufacturers_id)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=4 ;
[/SCR]