An audio interface simply converts the analogue signal into a digital signal that your computer can understand and process. A non-USB microphone has a so-called XLR (External Line Return) connection and can’t be plugged straight into a computer.
Music production is an entire universe, unlimited and full of challenges you need to face. You wanna be a music producer and you don’t know how to start, all you’ve done so far was figuring things out just by trial and error, then this article is for you. Here are "9 tips and tricks for music production".