You should try out the WoW druid forums or the Beginner's Forums.
The way it works is every level 10-70 you will gain 1 ""point."Pressing N or clicking on the icon on the bottom will open up a pane with 3 tabs at the bottom. These are called "trees".
Each tree has a specialty. The Balance tree is for offensive magic and debuffs, the feral tree is for shapeshifting and tanking/damage, and resto is for healing.
If you make a mistake, you must go to any Druid Trainer and click "I wish to relearn my talents." or something along those lines. The first respec will cost 1 gold, so be careful not to make a mistake. The next will be 5g, the 3rd, 10, so on and so forth. They go down a little each month (If youre up to 40g respec it'll go down to 35 after the month). The max is 50g per respec.