comparing fields from multiple entities in the same report (report builder 1.0)

Created a model that contains 2 entities. I open that model in report builder 1.0.  When I drag a field from one of the entities into the design area, i can no longer see the other entity or use any of the fields from that other entity.  I need to use fields from both entities in the same report (join tables).  In management studio i would simply write a query and join tables but i cannot figure out how to do this in report builder.  Once i select a field from one entity how do i select fields from more than one entity and drag them into the same report.