Looking for some advice on using a compute shader to control particle postions

So I am working on a galaxy simulation just for fun and I have run into some CPU limitations. For the simulation, I create the stars using a particle system and update the positions in Update(). This works well up to about 50,000 particles, but after that I get some serious slow down. I'd like to move the position calculations to the GPU using a compute shader to speed things up and increase the max particles but I've never made a custom shader before.

I was hoping someone on this forum could point me towards some resources on how to do something like this. I started reading the manual but honestly got a little lost. Does anyone know of any tutorials out there that deal specifically with using a compute shader to update particles? Any advice would be really helpful.

 

Simple example - animated 20 milions particles (total 120 lines of code ):

See two source codes in video description. Apply CS script to Main Camera, and set material with shader.