SSH or secure shell is best and secured way to connect and remotely manage your computer from anywhere
but most of the time people  use it from terminal which is text-based CLI . Its really difficult for beginners to transfer files using secure copy command (scp ) .
If you want to transfer files in GUI mode here is the quick and dirty way

1 : open file manager ( Nautilus ) and click on file  connect to server

2 : fill up hostname or server IP, choose port 22 , and the folder that you want to mount and finally username and password , and click connect

3 : after connection automatically mounted folder will open , then use that folder for normal file operation like , drag and drop like operations

5 : after transferring data unmount the location or keep it it depends on you

Watch it in action

Enjoy transferring file over ssh