how do i ad alexa html info to every page?

i want to add alexas code to every page.i don't know anything about this or very much about computers.i am doing this to be certified by alexa. tell me simply.where do i go to start to get into the back part of my site and then where do i go and what do i do to copy and paste this code to every page.

A link to your site would have been helpful in pointing you to the exact file....BUT

In a copy for your template structure of tpl_main_page.php (FTP it to your pc)
Open it in a code editor and paste the alexa provided code probably at the end of the file but before the closing

hi

i would also like to add Alexa to my page, I cant find the right place in my templates my page is https://www.nammi.is

Step 1: Go to Alexa and click on “Site Tools” in the upper left hand corner and then click on “Alexa Site Widgets” on the following page. Step 2: Enter the domain name of the website for which you’d like to display traffic data for on the widget. This would usually be your own website assuming you want to display your own ranking on your site. Once you’ve entered your domain name click the button labeled “Build Widget” and your HTML widget code will be displayed.
Step 3: Copy the HTML widget code to your clipboard by selecting it all, right clicking with your mouse, and then choosing copy from the right click menu.
Step 4: Login to your WebStarts account and choose to edit the page you’d like to add the widget to by clicking the small pencil icon next to the page name in the dashboard view.
Step 5: Once your page has loaded in the page edit view click “Insert” from the toolbar menu and then click “HTML Code”. You can now paste the HTML code in the area provided and click “Ok”. The widget will be added to your page and you will be able to drag and drop the widget wherever you’d like it to appear on your page.