if Cam:GetBroken() and Cam:GetInstalled() then
surface.SetTexture(OfflineScreen)
elseif !Cam:GetInstalled() then
surface.SetTexture(NotInstalledScreen)
else
self.RTMat:SetTexture('$basetexture', self.RT)
surface.SetMaterial(self.RTMat)
end

The only reason this addon is public is because it wouldn't work on the server it's used on if it was friends only or private. It doesn't work without editing and you need to have CCTV System by ToBadForYou (which is on Gmodstore, and costs money, 6 dollars 99 to be precise). The addon on our server also has modified code for this to work, which I cannot release with the addon for obvious reasons. If you have the addon and you want to get it to work subscribe to this addon and decompile it with Gmad to get the textures, then place them in the addon's materials folder and delete the old CCTV offline screen, and then go to lua > entities > tbfy_cctv_screen > cl_init.lua

The code you need to replace is at line 99 (use Notepad++ or another text editor that displays line numbers to find code).
Replace the code from line 99 to line 106 with the code in the above comment (I could not fit it in this one).

Where do you find this in entitys?