FETCH DATA FROM SUBFORM TO FORM

FETCH DATA FROM SUBFORM TO FORM

Hello, I have the form named "Loan application", and another form "Client's transactions" hosting sub form named "Group members." 
Loan application form has the field called "Account Number" and a sub form "Group Members" has the field called "Account."

ACTION/EVENT IN NEED: If the data entered in Loan application (Field account number) is equal to Data stored in sub form Group Members (Field: Account).

RESULT EXPECTED: Fetch the sum of "Savings_Collateral" data from Sub form "Group Members" and place the fetched data to "Collateral Available" in Loan Application Form.
can anyone help me with a code to  accomplish this? my email is grggvny@gmail.com