From Design Problem

My first try on a relational database! I created an Access 2003 database with two tables, linked by a one to many relationship. I created a form based on a query with both table details. The form enables access to a data field from the related table (the one in the relationship) via a combo box. This works fine. However, I have trouble to display on the same form other fields form the selected record. This might be trivial to many, but I really would appreciate some general direction on fixing this. Regards, Wilfried