the fastest way to manually listen to a frequency..
when scanning hit HOLD, type in the FREQUENCY, hit HOLD.
so
HOLD, FREQ, HOLD.
and for a conventional system
i don't have a 15 so try this as a good guess
hit menu, program system, hit yes
turn the knob to highlight new system, hit yes
conventional, hit yes
confirm, hit yes
turn to highlight edit group, hit yes
new group, hit yes
turn to edit channel, hit yes
new channel, hit yes
INPUT FREQUENCY, type it in and hit yes,
to put in more hit the menu button as a backspace and put in all you want hit scan when done.
you can go back and put in all the names later.