malem alarms are brilliant.
we had the one that clipped on the pants - there was no need to wear two pairs or drynites over the top - it literally clipped onto the fabric and if the fabric got wet it made the connection and started the alarm.
ours was an 8 tone and vibration - which one do you have?
the alarms come with very detailed instructions in the box - and a chart (stickers or stars, whatever) which we didn't use, but it gives you the chance to count your 14 dry nights accurately lol.
essentially - when the alarm goes off he needs to wake up fully and go to the toilet and empty his bladder. lights on - awake.
to start with the alarm might not wake him - that doesn't matter - as long as it wakes you, and you wake him - fully - lights on, awake and empty bladder.
but read the instructions - it is very very clear exactly what you have to do.
essentially there are two reasons for night time enuresis - hormonal which can be 'cured' (or at least mimicked) by desmopressin, or just very very deep sleeping, which can be 'cured' by using an alarm,
or, a combination of both.
dd1 was just deep sleep (she had been to enuresis clinic for 2 years and tried desmotabs which had not worked, as well as lots of utterly pointless measuring of wee out lol) - the alarm worked very quickly for her - within a week she was waking herself to go to the toilet before the alarm went off.
ds1 is a combination boy - the desmo does help, but he still sleeps too deeply to stop a gentle leak he's had a whole host of scans/ tests etc.
i'm a big fan of alarms. and neither of my (bedwetting) children are trauamtised lol, they were more traumatised by endles swamping of beds through drynites.
and i was more traumatised by the endless laundry.
it is just one of those things you need to work through though - dc3 here was dry day and night long before her older bro and sis - she used to ask me if she could wear pull-ups to bed too. (no!)