[Intrude]

The first thing you have to do is find the person's phone number. Then add the number to your contacts and name them something you can remember.
Click on the ghost in the top of the snapchat app homepage.
https://imgur.com/a/kbUZL

Then click add friends
https://imgur.com/a/oWa8y

After that click add from contacts.
https://imgur.com/a/2TJCj
Then click continue
https://imgur.com/a/RjZpL

Now if the person has registered to Snapchat with the specified phone number you should see this next to the specific name in your contacts. Sometimes they have their full names as their Snapchat names so it is easy to find other information.
https://imgur.com/a/R5HFy

I know this is not much but I though it may help some people. 🤝

[ZuGgY]

Pretty simple, knew about this already, but thanks for sharing, nonetheless.

[Mi2414]

Nice informative thread, I personally already knew this but this will be a good addition to the section. Thanks for the nice guide mate!