account affiliate affiliates allows code direct link piece product products program purchase sell sends settings setup sign sign-up site understanding url visitors website

I've already setup the affiliate program.

Maybe I'm understanding wrong. Is there supposed to be a piece of code that allows the direct purchase of the product on someone else's site, or is there only a piece of code that sends visitors to my website where the product can be seen?

You get an affiliate sign-up URL. They sign-up and "they" get a link using which they sell your products. You can sign up as you own affiliate to see how it works.

what do they see in the account?

can they change the products, and settings?

Affiliates can't change product settings. Best way to see what they see is to sign up as one.