In the data modeler browser, I am aware there is a way to choose a foreign key in an entity, in a foreign key properties menu (under "associated columns").
However I'm having trouble finding this menu.
Any help will be appreciated.
Toggle on the relationship button in the toolbar.
Click on the parent entity, then click on the child entity. The line will be drawn AND you'll get a properties dialog for the relationship.
Or if the line is already there, simply double-click the line.