Ah I see thank you. Then my steps should be:
1 - Create a new dbspace file and size it to 1GB to start as John posted.
2 - Alter tables to the new dbspace (is this only possible 1 table by 1?)
3 - When I need more space should will I be able to do it or do i need to create it with that reserve command? I could somehow add more space from 100 to 300 mb but not it's greyed on on scc.