Access Forms

I am a novice Access programmer. I created a customer management database with one table but with many forms to input data into different sections of the customer record. I have a main form with pop-up buttons to access the other forms. When I open an existing customer record on the main form I want that record to be open when I open the pop-up forms. I have a field for the Customer number and the Customer name on each pop-up form and it does not stay with that customer as I move from form to form. How can I accomplish this task?