How does "taking power" actually look like?

I keep thinking how Marxists talk about seizing state power so that capitalists/fascists don't, and just realized, I actually kinda struggle to envision this.

We're not capturing a flag, getting on the president's podium isn't gonna let you just dictate the people, so like, exactly what locations are we seizing and how are we using them to free the people?

(I probably need to read what is to be done)