is there documentation on backup function

hi
is there documentation on the built in backup function and if so can one provide me a link.

i enabled domain backup went to tools and there is only a restore button.
1, how to manually start a backup
2, if the backup is automatic what days does it run, what times
3, where do i go to set my own times schedule
4, if a user on front end writes to the db while backup is active what
effects will the user experience

thank you
TL

ok no need to answer this.
and for other newbies out there like me to linux, cron jobs is where jobs are automatically carried out and in my case "backups" are included too.