help with building creation

[Shadowfield]

Hello, I'm new to Hammer, but I'm figuring most of it out for myself. However, their are still a few things I can't get quite get:

1) For creating buildings, I'm guessing that I have to make them manually, and that there aren't any already made ones available. So how can I make my wall brushes triangular at the top so that they are attached to the roof? Is there a screenshot directory where I can see how Valve made there buildings?

2) How do I only select one surface of a brush to apply texture to. At the moment, I can only select the entire brush.

I had something else, but I can't remember. If you can help me with my simple problems, it's much appreciated.

Thank you, Shadowfield.

[Youme]

1) the clipping tool. Its down the left hand side
2) open the texture application window and THEN click the face you want.

[Shadowfield]

Great. Thanks Youme!

I remembered what I forgot. To rotate a brush, is there an alternative to using the rotation handles, where I can enter a numerical value?

[Youme]

tools>transform