How to add a nickname in ICQ app?

here is icq app so to add a nickname just tap on settings and then just tap to create nickname people who don't have your phone number can search for you by nickname uh acceptable character the roman alphabet digits period underscore and then it will just check if this username is still available so it's still checking so it just takes a while but anyways uh that's basically what it is and then you can just tap save in the top right