Suppose I lost my phone and I could use find my phone to find it. The problem is I don’t have my phone in order to find my phone with. I don’t have a computer I don’t have a laptop All I have is a phone. How on earth would I use find my phone to find my phone?
You don’t, if you have absolutely no way of accessing the internet or a phone network other than the phone you want to find, you’re out of luck and have to find it manually.