Go to finance 

Click on banking 

Select deposits for the relevant bank account 

Click add deposit

Enter the date 

Choose the client 

Select the payment type 

Select the credit code. This default to Trade Debtors. Only change it debtors loan account if your have no unpaid owner invoices to apply the credit against

Enter the amount inc GST

Enter a description 

Allocate the payment against outstanding invoices 

Click add deposit