Kayn's playstyle is very simple. Starting with Raptors, then with your E go straight to Crugs. After that, Red and then wolves and before doing Bot side skuttler, do both Blue and Gromb at the same time focusing first Gromb to give you that extra healing. After you finish skuttler you can either gank Bot, Mid or even take Top side skuttler and gank Top or Mid. You should, as a jungler, keep truck of enemy jungler's movement all the time, as much as you can, and be aware of your laner's positions in case you want to do an objective. No objectives mean harm for Kayn, but Ocean drake if it is the first drake coming up. Due to the Slow and Attack Speed reduction, killing it will take way too long for Kayn, giving enemy jungler the opportunity to either gank a lane or steal the drake.