1. Offsets sometimes change on a game update. If you have the wrong offsets you cant be banned for it the cheat just wont work.
2. To test cheats and not get banned right click on CSGO in steam library go to properties and set launch options and type -insecure the game will load without VAC.
3. Internal is a cheat that needs to be injected. External is something like a .exe
Hope all this helped!