Looking for an entry level simulations guide

Hope this is the right place for asking for something like this. I want to get into simulating UAVs through gazebo(+ros) and px4 so I set up everything as according to the documentation. I wasn’t expecting the scope of a full environment to be as overwhelming as it feels. I already did gazebo’s and ROS’s basic tutorials, but i am still not fully aware how to work with these two, plus px4 on sitl.
Are there are novice guides/tutorials that one could follow in order to better understand how everything works together?

https://dev.px4.io/master/en/simulation/

Thanks, but I meant something other than the official documentation, since that wasn’t enough for me to get a good enough grasp in order to start coding my own stuff

@alni Not sure if I know any better source of reference, but it would be better if you could point out what information the documentation is missing, so that we can improve the documentation.

I was looking for some more explained examples like the one found in:

But specialized towards other type of goals.
This might be somewhat exiting the extent of what the documentation should provide, and I should look for said examples elsewhere.

@alni Okay, so next question, what are you trying to achieve? what do you need an example of?

The end goal for the project I am currently on, would be having multiple scripts that could inject faults on different components of a UAV(sensors, rotors, etc) and as a result, it’s behaviour within a specific course would change.
In order to get started, I’d like to write a script corresponding to a flight behaviour, like, fly up 2 meters, fly horizontaly 2 meters, come back, land.
I have some basic idea on how to do this through a ROS package, but I’m not sure how I would initiate it through PX4, if I can even use the same package, or if I would have to write something specific to PX4.