I'll try to explain, so bear with me.
I start with the "Panel Arrangement" first, add the columns and rows you need.
Tick the various transoms/mullions, the way you want to divide the window up.
Go back to the "Series Selection" Select the type of window, for the OP elements 1,2,3, etc...
Now in the "Operable elements" the windows should be listed.
Adjust each window by using the grid numbers to place them where you want.
So (Bottom Left corner to Top Right corner, might be 0.0 to 0.1.
Hopefully that helps.
cheers