That's correct ... pressing the SEL (play/hold) button while the channel/talkgroup is active sill hold on that cahnnel/talkgroup. If the radio starts scanning before you hit HOLD (but before another talkgroup becomes active), you should also be able to press the LEFT arrow button and return to that talkgroup. Then, you can press SEL and monitor that talkgroup.
You can also step throug/browse objects and when you find your talkgroup of interest, press SEL to hold and monitor that talkgroup.