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?
get to a web browser and go to www.icloud.com and then findmyphone app.
No computer though
Other people have computers - friends, family, etc… Libraries, hotel and apartment lobbies, community centers, etc., frequently have them available for free use.