I might make a simple video tutorial explaining how to do that in gmod/sfm but until then this should help you: http://psteamcommunity.yuanyoumao.com/workshop/filedetails/discussion/911038356/1319962329030732212/

Animated gifs for the computer monitors work pretty much the same way, just need to make individual frames and import them into vtfedit. Also ask Apple what files you would need to replace and where for these computers as I do not know and do not have the time to decompile the ddon