Connect your digital audio interface to your computer via the USB ports on each device. Popular digital audio interfaces include the M-Audio Fast Track series, the Edirol UA and FA series, and Tascam's US series. Connect the flatter, thinner end of the USB cable to the computer and insert the thicker end into the audio interface. Some audio interfaces require power from an external adaptor, but many others can be powered via the computer's USB port.
Turn on your laptop and open a digital audio recording program. Popular software applications include Apple's Logic, Digidesign's Pro Tools, and Steinberg's Cubase. If you do not have any of these programs, you can purchase one from a local music shop or order it online. There are also free alternatives that you can download from the Internet, but these programs typically have limited functionality and quality.
Activate your audio interface within the recording application via the "Preferences" or "Options" menu. You will need to consult the user manual of the specific application you are using to get detailed instructions for this process.
Connect your microphone to your audio interface with the XLR cable. The female end of the cable should be plugged into the microphone while the male end should be plugged into the interface. Some of the most common microphones for portable recording studios include the Shure SM57, the MXL 990 Condenser, and the Rode NT1-A Condenser.
Connect your headphones or speakers to the audio interface and test the microphone. Create a new live audio track within the recording application and begin recording.