The amount of theory you need to know is totally individual by the way. It depends on how well-developed your ear is already, and whether or not you are able to put together satisfactory and logical chord progressions and melodies on your own.
I use FL Studio and it works well. Everything that you really need can be done in FL.
Curate a collection of samples. Percussion, synth, ambience, vocals, melodies, whatever. Collect sound.