If its the router, the 3612 and has an orange trigger type switch on the handle then the switch will need to be held on by you. I think the older ones had a switch like one for a light switch on the body which would stay on by itself.
Does it look like this one but without the bars attached?
I have a very old Makita router model ??? which is permanently mounted to my router table. It does not have the 'click' thing to hold the switch in, so I used a cable tie to keep it in. (also used wire, tape etc)
I'm sure the ones I've used stay on, pull back the thumb toggle, squeeze the trigger and whilst keeping the trigger depressed release the thumb toggle, should stay switched on.
Mine you have to pull the thumb lever to release the orange switch, releasing the switch cuts the router.
When I used mine I cabletied the switch on and used a switched socked.