I believe you have an adjustable quill type handlebar stem.
If you Loosen the bolt that goes through the side of the stem you can swing the front part of the stem upwards.
Also you you'll see a bolt going straight down through the middle of the stem, loosen this to lift the whole quill up. On the end of this bolt is a tapered wedge that can sometimes stick in place, the trick here is to loosen the bolt by one or two turns ( not to many as you'll damage the threads ) and give it a sharp blow with a hammer, you may need somthing on top of the bolt head if it's recessed ( a spare bolt or even a 6" nail would do )
It's a bit like life realy, the first time you do anything it can look difficult/messy/painful but before you know it becomes second nature.
Good luck