[dba-VB] transfer of data from sub to main form

Hi

In an Access database

On the form named frmPAInput, I click on a command button to open a subform named subfrmCharPA 

After entering several records that contain values on the subform named subfrmCharPA, I display a total value by depressing a command button labeled Refresh Total.  That enables the values of CharQty that have been entered on the subform to be totalled and displayed in a text box named TotalCharQty on the subform

I then can manually enter that value on the form frmPAInput, in a field named Observations. 

Is it possible to have the value be automatically entered from the subform to the main form?  And also if there were no subform entries, would I still be able to enter an observation value manually?

I have tried the wizard to generate the code but have been unable to get this correct.

Thanks

John