Split Screen for To Do

Hi everyone, 

I'm trying to get a split screen for my To Do. When I first downloaded the software, my computer asked me if I wanted to try it and I said yes; it was perfect! It moved all my other windows slightly to the left and my To Do list was on the right of my screen. I think I either closed the window or something but now I can't get that split screen back. I don't want it to be Pinned to my Start because from what I can tell, that doesn't move the other windows, it just makes the list sit in front of them blocking the visibility. And I know what I'm looking to do is possible because it was set that way previously. It's driving me nuts. 

I just want it to work like a split screen; 75% of the screen for my other windows, 25% for the To Do List. 

Any ideas?