I was in your position- had a nimbus wheel with a bad wobble and no experience of truing.
Here’s my thoughts-
Be careful with the spoke key, make sure that you get the right size because any slackness in the fit will strip the corners of the spoke nipples and make them un-adjustable when they get to a certain tightness.
My first key was a circular one with multiple slots for diff size nipples- after basically stripping many of the nipples I discovered that the key had two slots marked ‘15’, yet, on closer examination, they were not the same size!
probably the finest resourse for any bike/wheel related issue; has a good section on truing/wheel building.
Get into your head which way you need to turn the key to tighten/loosen- if you’re working the nipples on the lower part of the wheel, looking down on the inner part of the rim- it’s anti-clockwise to tighten, which is a little counter intuitive.
Do a search for other tips.
Good news is that it’s a unicycle so perfect trueness isn’t necessary (no brakes etc).
My Nimbus 29-er had a serious ‘jump’- early attempts at truing it were scary, I made mistakes (mainly forgetting which way to turn and ending up tightening when I was supposed to be loosening).
Do check your tyres mounted properly (I once started truing a wheel then discovered the tyre wasn’t on properly- the rim was actually fine).
Initially I did things the ‘proper way’ ie took off the tyre; when I realised my 29-er had serious issues and that, since the main problem was the tyre rubbing against the frame- I chose to true it with the tyre on.
I never did get that 29-er perfectly true, but I did get it true enough that the tyre didn’t rub. I believe that the rim was possibly damaged in such a way that perfect truing was impossible.
Since then I’ve actually built from scratch a 26" uni wheel, usning a fairly expensive rim and hub, which was a scary prospect. My experiences messing around with truing the 29-er were a big help. It’s well known that, it many ways, it easier to true a wheel you’ve built than true an old one; nevertheless, I’m quite pround of my hand built 26-er, which IMO is, to this day, still very true indeed.
In your position, if you want your wheel perfectly true, the you’ll have to get an expert to do it. However, if you work on it yourself, it may not be perfect, but you’ll learn a lot (just make sure you do some research, and take things slowly).