changing domains, how to add inventory/products to pages

Hi - I'm working in a website trial and trying to finish before I transfer to the old domain because I don't want to interrupt service for current clients access to pages, and I don't want to pay for two sites...

Want to make sure that when I transfer the trial site to the old domain that has the commerce advanced plan, that I'll be able to add products to my template?? Right now I'm seeing no option for that at all. In the old template I was using on my old site it was easy to add products to pages... the little plus. In the updated version (which I do really like!) I'm noticing I can't just add a button, I have to add a whole different section. And there are no product specific sections, they just have normal buttons for links/pages/files. 

Will I be able to add inventory to my web pages once I transfer it??