Changing which side image appears on in Collage - going insane!!!

Please help --- I am using 3 collage image blocks. I want them to alternate, the first with the image on the left, the next with the image on the right, and the third with the image on the left. These are the directions from squarespace -

"To select which side the image appears on, use the Image Position drop-down in the Image Block's Design tab." I don't see that option anywhere - I have tried clicking everything I can think of and googling. For something so simple, I really don't think it should be so difficult to figure this out! Feeling very frustrated with Squarespace at the moment. 

Of course I figure it out 2 seconds after I post -- if anyone else is having this problem. When you're editing the block, you click on edit Image, and then the Design tab within that edit image.