how to limit a form to only one record from a table other than form's source table

Hello,
So I have this simple database that contains only two tables. one contains customers information the other contains their payments.
I made a main form that pulls information from a query based on these two tables. When the user clicks on a record in this main form another form opens that shows the payments of this specific record, I did that using simple code in the where clause in on click event of the name field. My problem now is that when the user wants to add new payment on this second form they can enter a payment to any other customer not only the one that they clicked in the main form. How can I limit the second form to only the record that the user clicked in the main form. I attached my database.
Thank you very much

I've not looked at your db.
All you need to do is open the second form filtered to the required record i.e. customer.

ridders said:

I've not looked at your db.
All you need to do is open the second form filtered to the required record i.e. customer.

Click to expand...

Is not that what where clause supposed to do. I think when the form opens it is already filtered since it shows all the payment related to one record only, but still, you can enter a new payment unrelated to that record and I want to prevent that.

shwan said:

Is not that what where clause supposed to do. I think when the form opens it is already filtered since it shows all the payment related to one record only, but still, you can enter a new payment unrelated to that record and I want to prevent that.

Click to expand...

Try locking any controls that you don't want the user to edit

shwan said:

Is not that what where clause supposed to do. I think when the form opens it is already filtered since it shows all the payment related to one record only, but still, you can enter a new payment unrelated to that record and I want to prevent that.

Click to expand...

Yes it is correct, it is filtered but it is not locked to a certain record (Id).
You need a constellation know as Main-/Sub-form.