This is now my second day uncicyling on a 24" Qu-Ax Muni. I have heard that 20" is easier to start off on but I have had fun on my 24".
I have a few comments and questions though:
I can do about >50m most of the time on grass (then I start to run out of grass). I find it easier on grass because it’s a soft landing!
I can freemount quite a bit of the time but only then do a few rotations.
-I kind of put my right pedal slightly up and throw myself forwards so that my left pedal is slightly down to start pedalling. I presume this is not how you’re meant to do it!
I cannot idle though. Anyone got any tips of how to start? I thought that it was an easy thing to do but it’s proving tricky…
What’s the next step?
Thanks,
Mowcius
If you can go 50m on grass, I would recommend going to a paved surface now. It may seem a little squirrely at first, but if you can go 50m you should be able to land on your feet most of the time too.
Idling comes later. Better to get comfortable making turns to the left and right first. For mounting, scads of advice is already in here, search on freemount, free mount, rollback mount, static mount.
I can also do it on the road/pavements but not so far because I’m more worried about falling off… 
I can just about turn but it’s all a bit shakey at the moment.
I just suppose that the best thing for me to do is keep practicing!
Mowcius
If you can ride ~50M on day two, you’re doing amazing. Many people need to work at it for a week or two before they can manage that. I know I did.
Don’t worry about idling just yet. There’s lots of other good stuff you’ll need to learn first such as freemounting and tight corners, E.g. 90 degree turn on a sidewalk. Once you have these figured out you can start riding around the neighbourhood and expand your horizons!
Great work, and good luck!
After 3 days I can now do freemounts most of the time but often get my foot in the wrong place so fall off a few metres later…
I can now ride pretty much indefinitely on grass and roads (you do get strange looks riding a unicycle down the road, and lots of comments!). Turning takes a bit of arm waving still though…
I have also been doing some light off-road riding in the woods near to me, a few shallow ups and downs…
And I also have a few pedal scratches on my leg from when I went too fast and the unicycle tripped me up! 
Mowcius