Which books do I read, what videos can I watch? 

You willl most likely have to change to a dwelling fire policy.  

One time, I sent a video to a sub that was supposed to gravel a parking spot beside a cement driveway.

Section 121 will not apply to the gain allocable to any portion (separate from the dwelling unit) of property sold or exchanged with respect to which a taxpayer does not satisfy the use requirement.

Just know going into any builders risk policy, you're going to pay a lot higher premium than a typical homeowners policy or even a landlord/tenant dwelling policy, and most of the time you'll be getting a glorified ACV policy versus the RCV policy you're used to on your personal home.

I’ve been watching a lot of the videos and starting to feel more comfortable with taking the leap.

I’ve been watching bigger pockets YouTube videos for almost a year now.

I have listened to a few podcast and watched some videos.

I watched the 3:28:27 YouTube video "How to start an AirBnB business the ultimate free course" Rob posted on his channel Robuit and now feel equipped with everything I need to start my 1st STR.

The state legislation (SB 13) and the local guidelines both expressly distinguish between ADUs and JADUs and state that the 150’ applies to both of them, not just JADUs (“The accessory dwelling unit or junior accessory dwelling unit . . . may include an expansion of not more than 150 square feet”).