Karen,
There are no rules to a montage , its down to your creativity.
You can make them formal , like framed pictures on a wall . Or cut the figures out and make them into a crowd scene.
If you are lucky enough to have loads of photos , spread them out on a table and look to see which are the most usables ones , move the others aside. The ones that are left , move them around until they look 'right' .
Try them in generation order or all of the male or female line , see which appeals , to you !
It's all a matter of taste !
Have fun with it
Jim
