You do not need to learn the whole platform first. Use a small example, make one change, and check the result.
You need an invited Appify builder account and the builder address supplied with your invitation. If you do not have access, you can still read the concepts and agent reference.
Use made-up information for the first exercise. The pilot and its readiness checks are separate from permission to collect real customer data.
At the end: you should have a saved example project, understand where to change a view, and know that previewing is different from publishing.
Continue to Understand Appify to learn why the project, its data, and its screens are separate. If you already know what to change, choose a building guide.