Getting a value from one form to display in another

Getting a value from one form to display in another

I am not a programmer. I have two forms. Form A has three fields A1, A2 and A3, On Form B I wish to have a drop down list that shows values of A1 (Lookup). When a selection is made from the drop down list on Form B I wish to display the corresponding values for fields A2 and A3, adjacent to the DDL control on form B.

Can anyone advise how to do this plse?