first, you need to define the basic components related to your underlying data...
for example: parts, customer, hourly rate (for cost of labor) and etc
and each compoent should be stored in a separate table with associated fields....
for example: in customer table you may need name, (field 1), address (field 2), phone number (field 3).....
and each table you need to create a key (as index) so that multiple tables can be cross reference....
Buttom line is you need to create a bunch of relational tables and each table should contain very basic information (no duplicates)....

Good luck.