How can I preview cart while building it?

Very much a beginner here. I have the "start your web store with Zen Cart" book and it has been very helpful. I have modified how I believe I want the cart to look in the admin section. Uploaded a custom template and couldn't figure out how to view the cart to see if what I am doing is what I want. So then I tried a "free" template and again can not figure out how to preview it.
I have built websites in html with "simple" carts and understand some css. I need to move two of my stores up to the next level of shopping carts and think that zen will work for me but I am a WYSIWYG kind of person so I really want to preview.
Thanks for your help to what may be a simple thing I am missing.
Mona

Have you activated the template(s) you uploaded?

Admin> Tools> Template Selection

Also this FAQ section should help. https://www.zen-cart.com/tutorials/index.php?category=4

You can't really preview the changes. You can select the template in admin>tools>template selection and then click "Online Catalog" at the top of the page to see what the site looks like.

Thank you for your responses! I have moved forward in the design/cart options and believe I am on the right track
Mona