How to go about starting to build a 2D RTS

Hi everyone, im working on my second game and im just wondering where to start. I would like to go for the same kind of style as Prison Architect and Rimworld but instead go down a different route in terms of gameplay. I would like to make it much more like Command and Conquer. I have already started designing my sprite sheets and im ready to get some things into the engine. rimworld_01.jpg This is the style im going for but with my own twist.

These are some early sprites that I have ready to get in game and start messing with. Basically I want to start doing two things.

  1. Get the background sorted correctly ( The world ) so the sprites can float around in the world.

  2. Get these two chaps to start killing each other.


I just dont know where to start particularly but I would like to try and achieve these two things.

Would really appreciate some advice.

All the best.