Select the game in your library with a simple left click.

On the right side of the screen is a menu called "Links" Select the one labeled discussions, this will load a new page just stay calm and we'll get through this.

In the upper right hand corner you'll see a search box, try typing your issue there first.

Now a screen will come up with results, click the one that seems relevant. (In this example i'm blown away by the popcap on the african front maps and I have no idea what to do)

Wow! that's my issue, lets give it a click!
Wow! that's like the exact problem I was having! Now there's no need to post anything because my issue is fixed!

Stay calm, we can get through this; the first thing i would try is not being so specific on searching, if you're having a bug where your fallschirmjägers are wearing party hats, try searching "hat" or "fallschirmjäger" (or fallschirmjager), if that still doesn't yield anything and you've searched an awful lot, you're going to have to make a post.

Okay, First things first we're making a bug report lets get in the right sub forum.

Now triple check these pinned topics, even scan the other posts if you're feeling adventurous.

Okay, I haven't found my issue anywhere else, looks like I need to make a post. While this may seem scary just remain calm, calmly type your issue giving as much detail as possible.

Congrats! your very own bug report has been filed and will probably be responded to rather rapidly.