I suggest NOT trying to glue the brackets in place. If you are having a tough time with the screws, try predrilling the holes.
Take the bracket and place it where you need it to go. Mark the screw holes with a pencil.
Set the bracket aside for a minute and use a drill to start your holes for you. The screws will go in way easier if you have started the holes for them. Make sure the drill bit you use is a bit smaller than the screw you are using. If you are in doubt about the size of drill bit to use, then make a test hole in a scrap of wood and try to screw the screw into that test hole.
Make all the holes you need, then put the bracket up. Then do the other bracket or brackets.
If you don't have a drill then ask around a little bit. Usually SOMEONE has one. Even in my college dorm there was always someone who had a drill.
If you really really can't find one, then go buy a little cheapy hand held one from Home Creepo. It will come in handy for years and years. Or if you use it and then decide it is not something you really want to keep, then just return it for a refund. Tell them you were disappointed in its performance, because it was gutless. If you get one of the small hand drills then this will not be a lie... those things really don't have much power, but it will get this job done for you.