Here are some quick tips on some basic needs for an audio studio.

I set up my first studio in my bedroom, and little by little I evolved.

This video is only as guide because we need different things after all, like for example you may never need a microphone, and if you don't need a microphone you don't need a preamp and so on.

The bottom line is - start with what you have - and produce music. Little by little it will make sense of what you need and what you don't need.