Restoring from backup

[mreed]

I've read the manual regarding restoring, and I understand what to do, but,not having the experience of restoring from a backup, the question I have is: What will happen when you restore using the backup in Disk Utility?
If I need to restore from backup, do I clean install Tiger and then restore?
Do I erase and zero data and restore?
OR do I erase and zero, then clean install, then update to current version and THEN run backup?
OR something else all toghter different?
Considering this is the first full backup I've done since I've owned a computer, ( Retrospect is just too confusing for an "average" user...), I don't think the question is out of line.