Teach me how to use AI video generation platforms Vosu, InVideo, and HeyGen

This project is NOT to make the videos, but to teach me how do I make them myself. I need a short video every now and then, and a video cost one dollar. It is not worth it to post a project for one dollar

I need a clear, step-by-step instructions for each one of those three platforms, you must write them in NON_TECHNICAL manner; e.g. DO NOT say "create this" or "make that". Instead, say "go to this page, click on the blue button, then scroll down, and click on the red button"

Important: these platforms have various quality levels for various rate levels. I want a clear distinction because, in 90% of my videos, I will make the cheapest level

I need these three platforms (InVideo, Vosu, and HeyGen), but if you know of any that is equally good, but cheaper, please let me know