After you build and test your initial query, you're ready to create your final query.
Add the base table that participates in the other join — the table you excluded from the first query.
Add your first query to your record source.
As needed, join the table and query. Drag a field from one source to its matching field in the other. Remember that the field you drag is placed on the left side of the join.
When you finish, run your query to test it. Does it give you the answers you need? If not, change it, or change your initial query.