Select two adjacent rooms in your office space to act as the recording and mixing rooms. Pick the recording room based on which room is more insulated from the outdoors, if possible. Cut a window bay into the wall separating the two rooms; the bottom of the bay should be as high as a desk top and the entire window should be tall enough to provide visibility between the two rooms. Install soundproof glass sized to the width and height of the bay.
Place the microphone in the recording room and the computer and mixing board in the mixing room. Locate an empty space below the window bay and near the floor with the stud finder---it will not beep in these locations---and mark it in pencil. Drill a hole through the wall at the marked spot and run the microphone cable through the wall so it can connect to the mixing board. Drill another hole close to the bottom of the window and run the intercom's cable through the wall and mount the intercom speaker to the wall in the recording room.
Slide your stud finder across the wall and mark spots where the finder beeps. Nail acoustic paneling into these studs, spaced evenly across all four walls of the room.
Connect the studio microphone to the mixing board and the mixing board to the computer. Hook up the two speakers of the intercom system, with one speaker placed on the surface of your work desk. Test the microphone and intercom system with a friend to make sure everything is working correctly.