Lvl 1: You just want to hang around your adc taking some minions with support item and poking their adc with some flags (E).

Lvl 2: You are now almost at your demon mode 1v2 power spike so just wait around looking for a possible engage since you are very strong at this point.

Lvl +3: You have now acended and just the sight of their adc disgustes you! Thus wanting you to engage with E + Q + ignite and kill them asa fast a possible. The best outcome is that you engaage and take both kills and buy a dirk. You are now also free to roam the map and help the jungler. If you have aquired the holy dirk you will also be able to punish the enimies that are below you with divine retribution aka just 1 shot them lol.

Lvl +6: You will spend much time roaming with this champ and helping your jungler take objectives and invade since of how strong you are. Just dont forget that your adc might be 2v1 and being dived and you dont really want that either.

Jarvan is almost like a Pyke but tankier. Just lurk around in bushes waiting for for the perfect moment to engage when the enemies overstep or your teamates get ganked and turn the fight in your favour. DO NOT be afraid of taking kills even if your team if flaming you and especially in the early game. Think of it like this: You are a secondary jungler and will roam a lot. If you got the kill instead of lets say the adc you will inpact the map much more since the adc will just sit around botlane earlygame and just farm while you can be out there 1 shotting their jungler/top or midlaner with those kills and even taking objectives.

DM me on discord Simlito#1422 if there is anything you want to ask about.