How do I alter text that shows when checking out at shipping selection screen?

Where do you find / how do you change the headers and text of what appears here when a customer is checking out and choosing their shipping option:

Step 1 of 3 - Delivery Information
Shipping Information:

Your order will be shipped to the address at the left or you may change the shipping address by clicking the Change Address button.
Shipping Method:
This is currently the only shipping method available to use on this order.
United States Postal Service (1 x 1.50lbs)

any help greatly appreciated!
Thanks,
Kristen
https://www.heteromorphic.com/zencart

Admin - Tools - Developers Tool Kit

Enter part of the string (ex.: your order will be shipped) you want to change to see in what file it's defined.