Map Making

I have a few questions about making maps. 1. Do I start with a map editor type thing? 2. How do I open it if I do? and 3. Is it hard to make a map?

  1. Yes, Hammer
  2. Source SDK
  3. If you want the map to be good, then yes, it is hard to do.

How do i use Source SDK?

First, open steam.
Next, go to tools.
Then, install Source SDK.
Finally, click it and go to hammer.

Ok thanks.