I'm sorta new but the way I did it with my current map: start with the spawn then work my way up towards the cp. When I started connecting them together, I made the routes as individual rooms. That way, I could decide to either keep it like that and add some cover, or I can choose to vary the routes/flanks by adding walls, or just change them into chokepoints. A method I've been using is the "zig-zag" method, which I basically created rooms and placed a wall in the middle in each with a gap on one side creating a sort of "Z" path.