Pretty straight forward. Just be aware of ***** in little holes which like to fall out while you are not looking. Or come out while you are cleaning it in the solvent tank. If you don't get them back into their proper holes you can forget about it ever working again.
When you go back together use hydraulic oil. DO NOT USE BRAKE FLUID! That will ruin all the soft parts.
I'd be interested in parts availability. My engine hoist (older HF unit) likewise leaks down, but doesn't "use" oil (no leakage visible). Inquiries at local hydraulic shops haven't panned out, they say there is no standardizatiion on parts. HF says "maybe" I can buy a whole new ram, but they've never ordered one and they suspect it costs as much as a new hoist.