To download file using scp you need ssh username, password and host
1. First open terminal and type
mohit@ubuntu: scp <myusername>@<hostname>:<pathtofile>
Press enter
Yes to add to known hosts
Enter ssh password and done file start downloading to you local
mohit@ubuntu: ls
file will be displayed to you
Where
<myusername> ssh username
<hostname> like mohitsharma.net or whatever it is to be
<pathtofile> file path with filename to download like /var/www/test.sql
Note: use sudo with scp command if you don't have root permissions