New VTOL airframe. Getting started?

I’m a bit of a novice when it comes to software development.

I’m in the process of building a tail-sitting VTOL-capable aircraft. It has two motors, each motor can be tilted in both X and Y directions to provide roll/pitch/yaw.

But what I’m really asking is about the process for creating a new airframe configuration. It sounds like I will need to have a Mac/Linux laptop so that I can build PX4 and develop the new config? Is it just a matter of changing the mixer file to map the roll/pitch/yaw commands to servo/throttle control, or is there more to do on the software end?

Sorry for the basic questions, any help is much appreciated.