wix and paypal order form integration

I have a wix website where I created an order form, I hit the paypal button and correct amount displays and you can pay that amount, but I can't figure out how to update the description of what is being bought in paypal or how to update the paypal collection database with information from the paypal return. I'm using this for my alumni association to raise money for scholarships for students to attend Morgan State University in Baltimore. Once I have this integration, I can do this for future fundraising efforts, membership applications, and more. I know javascript but haven't used it and need tutoring/help on how to get this integration to work before Sunday. I've been working on it all week and I'm pretty close with a fake site.