https://threewheelermanuals.com/
Find your manual on the website, grab your favorite beverage, and read through.
It's always a good idea to check valve clearance on a new-to-you machine. Make sure the airbox is clean and check filter condition. At least clean any detritus out of the airbox if working on getting it running without a filter.
For priming the engine with fuel, I use a refillable, rechargeable spray can with gasoline. A little squirt into the intake and it'll fire right up if everything is copasetic.
These are simple machines and reading the entire manual isn't very time consuming, compared to modern automotive factory manuals that have a couple thousand pages and several separate volumes.
The story of three wheels and a man...