I keep seeing instructions saying press the "new" button to create a sales receipt. But I do not see any "new" button anywhere. Where is it?

Good day, lak84.

The sales receipt isn't a feature of QuickBooks Self-Employed. In this version, we can only create an Invoice. You can use this option to record your income. Then, you can just manually mark it as paid.

It seems that the steps you've read is for QuickBooks Online. You can check our Help page for the articles related to QuickBooks Self-Employed.

Also, I want to share this guide to understand more how this version works: QBSE Overview.

Please post again if you have more clarifications. Have a great day!