Hi, when you click "Checkout", do you see the "Save for later" page where you can add the items to a project, or click Save to download them later?

If you don't, check to make sure you have cookies and javascript enabled, and check any Internet security products you have installed, as some may interfere with sessions that the C5 may need to access the cart.

I do see "save for later"; I try to ignore it, and that does not work, the cart becomes empty. I watch the video, and eventually, my cart becomes empty. I click SAVE FOR LATER and my cart becomes immediately empty. I cannot figure out how to checkout with the free items.

Can anyone help? Thanks very much for your time and help.

When looking at free add-ons and themes, it is not necessary to use the check-out cart system. Scroll down the page and select the link that says "download archive" instead.
If you used the cart system, you need to either apply it to a project... or... select "Save for later". You can then download it from your Concrete Account Page (my account link in upper left corner, then select "transactions" in the right side-bar, choose "licenses", select "download archive").