Does Restore add to existing info, or erase?

I have a new machine and did a restore.

I need to bring some additional information across; when I re-run Restore does it erase what’s there and restart from ground zero, does it over-write what was already restored previously; or does it add to what’s there?

I brought CDR records the first time; if I bring them a second time will I end up with 2 copies of each call?

Should I reinstall from ISO and start from scratch?