Boxing is as much about speed as it is about strength, fitness is also key. Try doing plenty of cardio work, to keep you sharp in the ring. I wouldn't advise specific work-outs yet, as you seem like a bit of a rookie, try full-body work outs . There are plenty of guides around on YouTube, those will build up some decent strength and allow you to go on to specific work outs that target good areas for you, in relation to boxing, e.g. arms, core.
Core work outs are very important, if you have a weak core, you will find it difficult in any sort of fight, whether boxing or whatever, look up some good core work outs.
By the way, there is no quick fix, don't think you can suddenly become superman and beat up everyone, it'll take hard work and patience. Also, where abouts did you 'try out' boxing? Was it at a boxing club, because if it is, im sure they can provide you with some advise on what to do.
