The first step in recording your music is to get it into the computer. Your desktop computer’s sound card should have a line input jack, and that would be the one to use (NOT the Microphone jack). Connect the line input to the line output of your music source the way you would connect a mini-disk for recording.
Many laptops don't have a line input port so you will need to use the mic input if you record directly on your laptop. It can be done, but you will probably have to be very careful about the level of the signal you put into it. It will be very easy to overdrive it and wind up with very distorted recordings. A better way to handle it would be to use an "External USB Sound Card" such one from Sound Blaster.
A lot of the older turntables we use don’t have line output jacks so you might want to use the ones labeled “Tape out”. Don’t use the speaker connections!
We have found that the best way to record cues is to put them into a separate voice file, rather than on one channel of a stereo recording. DanceMaster can synchronize the voice file with the music file, and you can even adjust the timing of the cues relative to the music when you play them back. (More on that topic here.)
There may be a significant impedance mismatch between your turntable and computer, and you will get the best results by keeping the volume of the turntable low and adjusting the input gain on the computer’s line input up high. You might have to experiment to get the best results.
Likewise, when you are playing the music back, it is best to keep the volume on the computer low and turn the gain on the amplifier up as high as necessary for comfortable listening.
Files are best recorded at 44kHz (stereo if you are recording cues in the same file, mono if not) and compressed to either 96k or 128k samples per second.
The best way to record your music is to use a sound editor such as Audacity or Gold Wave.