In text:
1. I will show you how to make a mirror like this
2. find the nodraw texture
3. make a block were you want the mirror to be
4. Use the toggle texture tool, chose one side of your block
and find a texture called:"reflectiveglass001"
5. select the block and press Ctrl+T
6. Make your block to a "func_reflective_glass" and click apply
7. Now you're done!
that was helpful thanks!
Awesome
Awesome