Hey Precious-
If you have a keyboard with a seqencer then you can arrange your songs and use a TRS cable with a mini-jack on one end (to go to the microphone input on your computer) and the other end to your keyboard L(MONO) output.
Some computer soundcards come with audio editing software, such as Creative's Wave Studio. There is a free music software called Audacity that has pretty advanced features- But I recommend using Cakewalk's Sonar Home Studio. It is a relatively inexpensive software program and is very easy to learn and use.
I hope I answered some of your questions.