Hallo
you make a full export under
exp user/pwd file=xxx.dmp log=xxxx.log

and the other commands are optionally
full=y raws=y indexes=y owner=y


and the you import the data in you database under following commands.
imp user/pwd file=export.dmp ignore=y

This is the simple commands. You can better export your data and with another export your indexe.
So so they come again into your db.

Regards
Thomas Schmidt