The question for you is “with which aircraft”? Each aircraft has its own procedures and systems, even though the underlying process is fundamentally the same. When I first started playing this sim, I chose the TBM-930 for no other reason than it looked like a fun, powerful turboprop. I became somewhat proficient in flying it and using the autopilot and systems through some prior experience with playing flight simulators, but mostly from YouTube videos.
There were quite a number of new members complaining about the TBM’s autopilot not doing what they expected, especially when they were climbing out from takeoff, and when reacting to ATC instructions. As a first attempt at helping out the community, I created a “test script” that you can use to understand how to set up basic autopilot settings and execute them to understand the basics. You can find it here.
There are some excellent videos on YouTube that you can follow along with. If you come to the TBM, there’s a lot of members who I’ve interacted with here that have many hours with the aircraft and we’d be happy to help you understand. I’m sure you can search around and get some help within the airliner threads, too, as well as lots of folks who fly the smaller aircraft.
Let us know where you want to start and we’ll point you in the right direction. In the meantime, do a bit of reading on the basics so that when members use specific terminology you can follow along. I found this link that can get you started.
Given the amount of work going on stabilizing the game, I would say you’re better off looking to the community and YouTube to help you understand what you want.