I am looking to build a magic system for a story and I’m not sure how to do it.

I am looking to build a magic system for a story and I’m not sure how to do it. I know what it will be based on and purpose. Basically, it’s two core components will be trust and philosophy behind language( words are very important). Though it can and may be used for violence i want to explore who it effects specifically gender and sex norms and belief systems and stuff like that.

The main couple is polycule(closed) and use poly fidelity to solve a succession war crisis( temporarily) but the they lose a war and the mc losses his memory and is exiled so they leave to find him and get him back so they can rule( but really they love him).

I’ve seen the most intricate and unique magic systems and want to build one on my own but I don’t even know where to start. Some useful pointers would be nice.