Double-click the desktop icon to launch your preferred digital audio workstation.
Open the "File" menu and select "New Project," "New Session" or "Open New." The exact command for opening a new recording varies slightly between programs.
Import the relevant audio files. The exact process varies slightly, but you typically execute this command via the "File" menu. For example, in Apple's Logic program, click "File," "Import Audio" and then select the files from the browser. Both pieces of audio will open in their own channel. The audio will be represented by a sound wave graphic, the peaks of which signify high volume.
Open the "Tools" menu and select the "Trim" or "Scissors" tool. This tool lets you snip unwanted audio from the file.
Click to the immediate left of the first sound wave in each audio file. This trims off the silence at the start of the track. Drag each audio file to the left to line them up together.
Click "S" on the first audio track, this mutes the other audio so you can hear the first audio in isolation.
Click "Tempo" and select "Tap Tempo." Hit "Play" and tap the space bar in time with the music. This enables the digital audio workstation to detect the tempo. Repeat this for the second track. It's unlikely that both tracks will be the same tempo. The tracks need to be the same tempo, otherwise they will clash.
Click the audio track with the slower tempo. This highlights it and assigns subsequent edits to this track only, rather than both tracks.
Open the "Effects" menu and select "Time Stretch" or "Tempo Change." Different programs have slightly different names for this effect. In the "To" box, enter the tempo of the faster track. This makes both tracks the same.
Trim out alternating sections of the two tracks, so there is silence in one while the other is audible. Use the sound wave graphic as a visual guide when doing so.
Highlight the areas of audio next to each trimmed section and add a cross-fade. This makes the transition from audio into silence smoother. You typically add a cross-fade command by clicking the "X-Fade" tab in the tool bar.
Adjust the "Gain" for each audio track so they are at the same volume. Gain refers to input signal strength, not volume. If one track is naturally louder than the other, reduce its gain to compensate.