you are using a ssh app for connecting to your computer. first of all, to identify a computer, you need one of three thing. the name (e.g. MyComputer), the ip address (e.g. 192.168.1.10, or 231.12.53.2) or a mac address (that should be hard coded into your hardware device). you don't need to fill in all three of them. then you need to fill in the username and password on the computer. the ssh key is another password set by ssh server, fill it in if you have set. port 22 is the standard port for ssh. some people will change it other port for whatever reason.
be careful when using such app