Scenario-1 : Loss of non system data file

Method-1(not advisable)
1.offline the tablespace.
2.Restore the lost datafile from the latest backup.
3.Recover the lost datafile.
4.Online the tablespace.

Method-2(Advisable)
1.Offline the lost datafile.
2.Restore the lost datafile from the latest backup.
3.Recover the lost datafile.
4.Online the datafile.