Just start with what you got, do some recording/mixing, listen to the mixes - have others listen, too - and figure out how to improve whatever needs improving.
Unless your mic is a USB one (hopefully not) you need to add an audio interface to connect the mic to the computer. You'll rapidly find the built in sound card on a computer isn't satisfactory for anything much more than a Skype call.
Money. just kidding but not really. stuff cost money and the more you learn the more you want. research is the key. there is tons of knowledge on this site so ask questions. for the basics you need a good computer, a decent interface, and a good mic. when you say Hip Hop will you be recording vocals and sampling everything else? if so you don't need need much for that.