Questions

oh, that's very easy!
you log in to your cPanel, go to Files > Backup
there you will have number of full and partial backup options.

if you never made a backup press Download a Full Backup this will generate a backup and send the email to your admin address when done (that can take some time, depending on the number of files you have there).
a backup can be made locally (ie in your web space on our server) or to a remote server.

once made the backup file(s) will show in Backups Available for Download - click on that filename to download -- the backup will be in compressed .tar.gz format.

it is very important that you make backups of your site, unless those are included in your hosting package ie. made automatically at specific intervals).