This is a tutorial for making a small map to help out people who want to make maps for gmod, counterstrike, and half life 2.
Step 1: Open Up Steam
Open Up Steam. Look for the tools tab at the top, and, if you havn't already done this, download the tool "Source SDK". If you have it then open it up.
Step 2: Enter Your Settings
This is where you start to customize settings. If you want to play half-life 2 or garry's mod with your new map, choose orange box engine or the ep1 engine and then set the game to half life 2 (or any other game for gmod).
If you want to make a counterstrike source map, use the ep1 engine and choose the game counterstrike source.
For me, I'm going to use the ep2 engine.
When your done choosing the settings, doubleclick "Hammer Editor" at the top.
Step 3: Click on the brush tool
To make a new map, go to file at the top, and then click new. When you click that, 4 boxes should pop up in the middle mass of the window.
To start making the base of the map, click the brush tool. This is the small square icon in middle left.
Step 4: Click and drag a box
To make the base of the map, click and drag on one of the windows, but not on the top left box. Make a box of soem sorts. When you make the box that you find to be right, press enter.
Once you press enter, press Control+H. A window should pop up. In the input, put in "-12" (negative 12). Then press enter.