General :: Selecting Specific Table From Listbox?

I have to make a multi-user manage database.All the usernames are sorted in one table and exported to listbox in Form.For each user there is a separate table with 3 columns where i must fill information from listboxes.The listbox (there are 4 listboxes, one for users select and 3 for different parameters) are located in MainForm where you select the information.My question is how can I select a specific username(table) from the listbox and fill the information from the other listboxes to the selected one?

The usernames table is named - Clients

each table for separate user is named client1, client2, client3 etc.

the form where you choose what to select is named Fill form.

The listbox for users is named - List71 And the listboxes for parameters are named - List75, List77, List79 Also there are 3 textboxes with calculated fields that i also need to insert in the specific user table.