1. Open the properties of Garry's Mod from the library. (If you don't know where that is search it up.)
2. Click on the "Local Files" tab.
3. Click the "Browse" button.
4. Find the folder named "garrysmod" and open it.
5. Find the folder named "cfg" and open it.
6. Open the file named "autoexec.cfg"
7. Type (hud_quickinfo "1") without the parentheses.
8. Save and close the file.
8. Restart Garry's Mod, and enjoy!

If you want to undo your changes then just change (hud_quickinfo "1") to (hud_quickinfo "0") without the parentheses.