PayPal Payment

I'm trying to figure out how to set up PayPal for my members when they join. I have set up membership levels. I upgraded my personal PayPal account to premium. Is there a document or forum post that walks you through this setup and how to test it?

Thanks.

Do you mean so they pay right wen they join?  Can't be done.  They have to join first and then upgrade.  We begged for this in D6, so it was a big disappointment that it was left out of D7.

Pay when they join would be great, but I'm just trying to set up the payment when they upgrade their membership from standard (free) to a premium level. I've created the level and pricing, but not sure how to go about setting up Dolphin payment options and the PayPal side.

Modules > Payment > PayPal

What Process Type and Connection Type should you select?

And then what do you need to do on the PayPal site to make it work with your Dolphin settings?

I have IPN enabled but PayPal asks for a return URL, what should that be?

I've set up some sandbox accounts on PayPal, do I really need them?

I'm struggling to find decent documentation.