Ooooh well you can still do a simple curves adjustment with DPP.
View your tool palette (ctr+T)
On the "RAW/RGB/NR" tab selection, pick RGB.
You will see three bar graphs. One is green, one is red, and one is blue. There is a line (x=y if you know math) through the middle of the graph. X=Y is the standard setting. You can manipulate and "curve" this line to your will. If you click once, it will change the entire curve. Pulling down changes brightness to dark. Pushing up changes brightness to...well...bright.
If you use two anchor points, you can make part of the image darker and other parts brighter. This effects contrast. I suggest you stick with two anchor points until you figure out what is going on.
Do you know what that graph is called? It is an EXTREMELY importiant element of photography ,especially for those determined to do everything in camera, called a histogram.
Reading a histogram can be fairly complicated but basically everything to the left is dark. Everything to the right is bright. How high the graph goes at a given level determines how many pixels are that brightness. If there is no graph, no pixels are that brightness.
You can get pretty fancy, but there are two *basic* ways I suggest you use curves:
1) Set 1 anchor point in the middle and 1 anchor point above it. Play with the anchor point above until it looks right.
2) Set 2 anchor points symmetrically 1/3 up the graph. You have 16 squares for measurement guidance.
After you get the hang of it you can make it more complicated, but practice and figure out the basics first.