Ok so yorick is an off meta pick, there's no way around it. it's an intresting pick and does work if your enemies don't know how to play around it, but it's an off meta pick and it can be countered by smart enemies. So good luck with it and have fun.

Weirdly, even though you are off meta yorick can hold his own against enemy junglers very well espically if you did an early back and bought the two doran's blades, if you have about 3 ghouls you are able to win 1v1's with almost any jungler given you are within about 2 levels of them, and if you have your maiden up and a few items it will be very hard for junglers to hurt you. However your matchups against enemy toplanes are about the same as any yorick guide, so I would reccomend veiwing this matchup sheet made by someone more talented then me, it's a bit out dated but still accuratee.
https://docs.google.com/spreadsheets/d/1YsDgPYC0yy9NswwGcNFQ6P1F2gt2wObEhATOJ***uWg/edit#gid=393895688

Ok, I mentioned that yorick has a weak early game, but this excludes one point at level two. If you start redside jungle and get a leash and use your q to finish off the red buff, you can go to raptors and smite the big one and use your q to finish off the little ones until you have 3-4 graves, and after the fight summon them. This will slow down your clear but getting the ghouls means you are very powerful, next if you want to gank early go to botlane and hit your e, if you are doing this without clearing krugs, you will not have level 3 so that means no cc, so make sure your botlane knows you're coming in. The damage from your ghouls will be enough to get a kill on about 50% hp targets, and since the bot lane will also be level two it makes it easy to get in there, your q will also do massive damage with fleet footwork, so you can easily snag a kill or set up your botlane.

Yorick has a problem with any contested objectives, is that he needs his ghouls as they are huge damage dealers against any dragon herald or barron, he can do dragon and herald without ghouls if they're uncontsted but he struggles. So you need to either have maiden active or have ghouls from clearing a camp. if you have the ghouls especially at level 3 you can easily grab crab even if the enemy jungler is there, smite to secure crab if needed. with objectives like drakes and barron you have a larger smite thanks to the extra damage of your Q. This damage is based on your AD and level of Q but as a rule of thumb at around level 4-6 it should be doing around 200 damage so smite at 1100, at level 6-10 it should be doing around 400 at level 11-14 it should be doing 600-700 and at level 14-18 it should cap at about 800 depending on what you build, keep in mind if you build more defensively this will not be the case if you are confused the number of damage the Q say's it does is added to your base AD so make sure you are checking that as well.

As a bruiser jungler you are not going to be able to gank as much thanks to yoricks low mobility, so you want to focus on farming and winning objectives becuase thanks to maiden yorick has an very good clear speed and does insane damage to objectives, when looking for ganks make sure you have about 3 ghouls if you don't have maiden and 2+ if you do, when going for a gank make sure you hit your e, you can use a chilling smite first if you want to make this easier as E will be your main damage for the gank, then try to bait out the flash if they have it, if you cannot bait out the flash/dash they have move onto the w to trap them, and then wail on them with your ghouls and Q. For diving I'd wouldn't recommend against full health targets unless they are very squishy, because you have no mobility tools you will be taking a lot of tower damage and be susceptible to cc, however if you are running demolish and have your sunderer, or your sheen you can simply take a couple plates off the tower to get extra money.

In conclusion yorick jungle is very off meta but a ton of fun and a real powerhouse pick if you know what you're doing, but also get's countered by high mobility champs.

Special thanks to youtube channel BaLoRi https://www.youtube.com/channel/UCUkOmvlRSUTonLAYn8XX9Ew
he's the main source of inspiration for this guide and the build is very similar to his regular yorick build, would reccomend checking out his channel as he does have some yorick jungle videos.