-There is no 3D touch on current ipad pros.
-4-finger swipe left/right to switch between opened apps
-4-finger swipe up to bring up multitask screen
-5-finger pinch to close app and get back to home screen (i think it's really 4-finger pinch, but nobody pinches with 4-fingers, except maybe the Simpsons)
-swipe left from middle-right edge of screen to activate slideover (secondary app on the right side). not all apps are available in slideover. to switch the slideover app, swipe down from the top edge of that column.
-once the slideover app is shown, you can swipe over some more to get a 50/50 split of the 2 opened apps ("split view")
-PUT ON A GLASS SCREEN PROTECTOR. only costs a few bucks and if you apply it correctly you can't even tell it's there. if you get even a little scratch on the actual screen it will cause a rainbow effect at some angles. in this case you will have to have the screen repaired for a ridiculous amount of money or you will die a little inside every time you see it. with the glass protector, you can just replace the protector itself for another couple bucks. trust me, it's worth it. the ipad pro 12.9 is all about the screen!