Akai MPC 5000 Reference Manual page 36

The 'Sequence' field continues to show the sequence number that is currently
playing,
The '>' field shows next sequence that will be played.
When next sequence is selected, you can start to play next sequence immediately
by pressing [STEP>] button.
When next sequence is selected, you can cancel selected next sequence by pressing [<STEP] button.
„
Press the [PLAY] or the [PLAY START] button to play back a sequence. At the point where you wish to start the recording, press the
[PLAY] button while holding the [REC] button. The MPC5000 will start recording.
If you press the [PLAY] button and the [OVERDUB] button instead, the MPC5000 will start the overdubbing.
If you press the [REC] or the [OVERDUB] button during the recording/overdubbing, the MPC5000 will stop the recording/overdubbing
and resume the playback.
„
Undo will only work when the sequence is stopped.
The LED of the [UNDO] button will be off and only the last added recording will be deleted. To restore the last recording, press the [UNDO] button
again to light the LED.