As mentioned, it will depend on which state you're building in and the cost of the build, as to whether or not you need to do the state government required owner builder course to get an owner builder permit. You need a permit to build so you have to do the course and provide proof of doing the course before you can go any further.
The other three resources outlined above – Is Owner Building for You, The Pre-planning Stage and Nail Your Build are nice to have, cost effective and super helpful resources designed to support an Owner Builder through what is a massive undertaking.
They are NOT accredited courses, nor are they a legal requirement. They're simply designed in consultation with two registered builder's to help Owner Builders simplify the process 😊