Questions about frontline plus for dogs?

I got frontline plus for my indoor dog... thankfully so, because as soon as i got home from the vet with him I found his first tick on him.. i was wondering how does this medication work? you have to squeeze out the medicine between his shoulder blades.. I don't know how that is supposed to kill the fleas and ticks all over his body? also, i put the medicine on him and did not remove the tick because I was afraid I wouldnt get the head out and I thought the medicine would kill it and it would just fall off.. I got home around 4 hours later, and the tick was still there and alive, so I removed it with tweezers the best I could. How long does it take to become effective? Thanks!