If you don't know SQL code, your best bet is to create a query in design view (it is much easier this way for new people). Just include the Customers, Types, and Orders tables and then select the fields that you want out of each. The query will view the relationship and be able to pull the related records and put them together. You can then base the form on that query. The query does the work of combining muliple tables for the form.
I don't have enough information to even guess at what the SQL code that you would need. The basic form of SQL code is:
- SELECT ___
-
FROM___
-
WHERE ___ (optional)
The following website will help you learn SQL if you want.
SQL tutorial
If you really don't want to have a query object as the source (I can't think why), then take the query that you created in the instructions above and then change to SQL view, copy the code and then paste it into the row source of the form.