This free Charmin toilet paper is on an all-Spanish site, so get ready for a lot of confusion and bumbling around. There's a prom joke somewhere in there.
What they want you to do on that first page is create an account with your name, email, password, zip code, and birthday as well as check the box at the bottom. On the next page are three terms of agreement that you just need to accept, then go to this page and log in with the account you just created. You'll then be able to request the freebie, but make sure you have your full address entered!
If you don't know Spanish, I'd suggest using Google Chrome to sign up for this. It has a helpful feature where it detects foreign languages and asks if you want to translate the page.