i realy need help and advise on building a home studio?

ok i am planning to make jsut a simple home studio...the purpose is just to record my vocal then mix it into the karaoke ...because i already have the beat so i don't need to make one....but i heard that u need a good mic that support phantom power (what is phantom power?) then an audio interface....but what are those buttons and switche on that interface i am so confused, do i need a sound board or a mixer...and what is a mixer do ???....plus so i need to put foam around the room so it won't make noise. i already know how to mix and use the software...all i need help is what to buy and what is the purpose and do i need to do anything with the room please help

http://buildahomestudio.com/