Your most basic Jungler start is Red buff
Right Camp
Inner Camp
Blue Buff
Inner Camp
Left Camp
Your smite is very important because it helps you clear your buffs at certain thresholds which speeds up your camp clear rate. Timing is everyrhing in this role. At base level it does 500true damage and after a few kills it does 1,500 when it evolves. Youll definitely need this when fighting Primal Fangtooth and Orb Prime.
My usual start is Red camp, right camp invade enemy Blue Camp drop a ward on flower and then gank Mid or Nearest Lane.
Your role as a Jungler is to provide and deny vision of the river and gank routes and contest objectives (Fangtooth, Primal Fangtooth, Mini Orb, Orb Prime). Secondly yes you are a sort of a support but with more value than sit back and watch you are considered an initiator. Whenever you show up in lane it should be ifeally when the enemy is positioned past the midway mark (the river) and your laner is capable of assisting you so you may secure kills on the enemy laner. Dont worry about losing the kill to your laner the inportant thing is you wiped them off the board and now that opens up opportunities for everyone else. Your options are to push lane and get some tower damage or back and buy items. Usually the courtesy is your laners got the kill so you farm the minion wave while they back and buy from the relief you just provided.
Another role you influence battle rythm. Whenever you show up in lane it should always be an oh crap moment for the enemy team. Because you have been warding or denying vision you allow your team an upper hand in pushing lanes and knowing the enemy team doesnt have confidence in leaving a lane. Be mindful this works both ways so often times youll have to keep an eye out for thr enemy jungler and if theyre causing a stir stay on top of where they are.