Not able to access course after purchase

I'm trying to set up these plug ins so it's easy to navigate the check out process.

I want them to click either full time payment or 7 monthly payments on the sales page. Then, I want them to redirect to the paypal page and then the account registration.

Is this possible? I don't want them to get distracted and decided not to join. Pay first, then registration.

Also, I want to be able to edit the "register account" type buttons. They are very hard to find on the page.