Connect a set of stereo cables from the turntable's output jacks to a set of input jacks on the amplifier or receiver, matching the red and white plugs on the cables to the colors on the jacks.
Hook up the second set of stereo cables from the amp or receiver's output jacks to the two jacks on the Y-adapter, then insert the plug on the Y-adapter into the audio input jack on the computer's sound card, typically found on the back of the tower. If the analog vinyl is recorded in stereo, the sound will be captured in stereo on the computer through the Y-adapter.
Open the audio recording software on the computer by clicking twice on the program name. The computer will have recording software that operates with the installed audio sound card. Windows and Apple computers have the software bundled with the system. Windows Sound Recorder is a common software package, for example. If the audio card was added to the computer later, use the software that came with the audio card; it should be listed under the same brand name as the audio card.
Switch on the turntable and amplifier, then place a record on the turntable platter. Position the tonearm over the record at the start of the desired track, but do not lower the tonearm yet.
Click the "Record" button on the computer software.
Lower the tonearm to the record to begin playback. The computer will make a digital recording of the analog signal on the record.
Click "Stop" on the software to end the recording session, then click the "File" tab and choose "Save As" to open a box for typing a name for the recording. Click "Save" to store the digitally converted recording on the computer.