READ THIS CAREFULLY

IF YOU DON'T READ THESE AND FOLLOW INSTRUCTION, DO NOT COME TO ME WHEN YOU'RE UPSET IF YOU GET BANNED.

Go to your windows hosts file (C:\Windows\System32\drivers\etc). Open it with a text editor. Add the two lines below to it.

127.0.0.1 api.garrysmod.com
127.0.0.1 cf-protected-api.garrysmod.com

Having issues editing the hosts file? Is it saying it's being used by another program? Start up notepad as an administrator, then go to file->open. Copy paste this in the file name textbox and press enter:

-NEVER CHANGE THE NAME OF THE INJECTOR UNLESS INSTRUCTED TO
-NEVER RUN THE GAME AFTER AN UPDATE UNTIL ATEE DECLARES IT AS SAFE

TO HELP AVOID THE GAME UPDATING WITHOUT YOU NOTICING, GO TO YOUR STEAM LIBRARY AND RIGHT CLICK ON GARRY'S MOD. SELECT PROPERTIES. CLICK ON THE UPDATES TAB, AND SELECT "Do not automatically update this game"

MSVCR100.dll is missing from your system?(x86=32-bit, try ARM if nothing else works)http://www.microsoft.com/en-us/download/details.aspx?id=30679
First, to inject properly you will need to enable quick alt tabbing. This is done by going to Libary->Garry's Mod->Right Click->Properties->Set Launch Options

Start the injector as an administrator.
Want to be able to inject at any time? This involves you disabling steam's overlay. Go to your friends list, right click on your name and click change profile name. This will bring up the steam settings menu. From there go to In-Game and uncheck "Enable Steam Community In-Game". If you do this, you can inject at any time without crashing. If you don't, then it'll be a bit difficult to inject at the perfect time. This is a personal choice on your behalf, and does not effect detection.

To use the injector, first log in. Then start up Garry's Mod. Once Garry's Mod says "Loading" click Ok on the injector to inject it. If you find injecting during loading to be difficult, inject it once you have joined a server.

Use arrow keys to navigate the menu, hold control and use the arrow keys to move the menu. Use the insert key to show/hide the menu.
To run clientside lua, make sure you have Client Side Lua and sv_cheats turned on.