Show name from one table, and a sum from another table.

Hi,

For instance: I have 2 tables.

1. Table1 has fields TenantID, TenantName,

2. Table2 has fields AmmountCredit, AmmountDebit, TenantID.

I need the following behavior.

In the detailed section I want my report to show a list of TenantName, and a SUM of AmmountCredit minus Ammount Debit for that Tenant (which will come from Table2).

How would I do this?  If a formula is involved, please provide an example because I'm fairly new to Crystal Reports.

Thanks

Aron