Replying to Fat tubes vs Skinny boxes/flat rails 

this may sound insanely dumb, but here it goes ahah. Started learning how to ride in the park this season and I’ve been getting more and more comfortable on a variety of tubes and rails. I’ve been able to get onto them and comfortably ride the whole rail about 95% of the time, learned how to FS 270 as well as pop/slide off both forwards and switch, but for whatever reason I don’t really know how to approach skinny boxes etc and all the ones at my local hill are well into nutcracking territory so I guess I want to have a more solid understanding before I put my future children on the line hahaha. How different are they from a traditional round rail/tube and what would be some key things to Keep in mind next time I get out?