You kinda have to be able to do both separately without thinking about them at all before bringing them together. Set the spin just before you pop, then once you pop and get the spin going take your trailing hand (right hand if spinning left) and put it into position for the grab (each grab kinda has their own spot, for example blunt is kinda just behind you) but DON'T reach for the grab, just put you hand there (this is why you need to be able to do both without thinking, aka muscle memory), then bring the ski up to your hand (again, hand not going to the ski, ski going to the hand). All the while you need to remember that you're spinning, so don't focus too much on the grab or you'll stall your spin and most likely eat shit. Once the ski is in your hand, hold on and get back to focusing on your spin, spot your landing, let go (this is obviously important...but there is a lot going on here), stomp it.