If you're struggling to work out the logistics of passive income, I'll let you in on my little secret: I can't get PayPal to redirect people after checkout to the right page either!
So I use Payhip.
It allows me to sell digital downloads so I create a buy now button on my sales page and use their link to the checkout page. I then create a password protected page on my Squarespace website and then when people buy via Payhip, I send them a pdf with the link to the password protected page and the password to access it.
Is it the "best" way to do it?
Maybe not but, it works for me. And Payhip takes Paypal which is awesome for me as I can't use Stripe. (I live in the UK and charge in dollars and unless I get a US bank account, Stripe won't let me change the currency)
So if you can't work something out either, maybe there's a different way you haven't though of yet.
P.S. Today is the last day you can get your membership for $67. After today, the price goes back up!