Have you heard of Google? https://www.petrockblock.com/forums/topic/how-to-run-from-usb-the-best-method/#post-100012 indicates you wanted someone else to tell you everything (it was the first Google result if you had bothered).
re your latest “please tell me every single thing i should do” post..
/etc is a directory. Are you at a command line? have you tried “cd /etc” ?
Editors? There are many you can use.. you could try nano or vi…. but please find out how to use them yourself. There are many sites that can tell you the commands to load/save files and add/delete text.
I am not normally so unhelpful but you really do seem to be seeking a 100% spoon feeding without doing much yourself!!