First, it is best to setup your company file and choose "Retail" as your industry type:

After that, you need to create "bank" accounts that capture your "PayPal" funds, Amazon funds, and "other" funds if you sell from other sources.

To create these accounts, start from Chart of Accounts:

From Chart of Accounts, create 3 bank accounts: PayPal, Amazon, Other (please do not skip this even if you are not selling on some of the sources at this point. It's easier to setup the account once rather than changing later)