Hi JosephF and welcome to the site,
Since the carby is already off this will make your job easier.
I suggest you read this by Rick Ramsey to familiarise yourself since as you said you are new to this bike stuff.
https://www.rickramsey.net/CRF230Fcarb.htm
Be careful it can be addictive and then the whole family wants a bike each.
Being a 2008 model your bike will have the tamper proof screw with annoying to remove cap as Neil suggested.
Honestly do yourself a favour and get one of these,
https://www.crfsonly.com/catalog/produc ... ts_id/1362
even if you only adjust it once or twice in the next 10 years your burnt hand will appreciate it.
I would grab the extra bits spring, washer and o-ring, because you will need them eventually or if you drop something.
Make sure the old O ring comes out of the carby and follow Ricks instructions and you will be sweet.
It is still hard to adjust but not impossible.
Jetting.
Firstly take the float bowl off over a plastic tray or cardboard box of some kind.
If the baffle or pivot for the float fall out, they will always bounce to some hidden place.
Use a good fitting screw driver and take your time, it will be cheaper that way.
Once you have the bowl off, confirm what jets you have and post it some we know where we are starting with.
You say the bike is stock, can you confirm it still has the snorkel on top of airbox and the baffle is in the rear of the muffler.
If I read things right Michigan only gets to 85 degrees in summer and freezing in winter.
You may get away with adjusting the fuel screw mentioned above to cover different seasons you can ride in.
The alternative is getting a 45 idle jet and installing that whilst the carby is off the bike. I would recommend probably just getting it anyway they are like $6 and the 230F are cold frogs. If it is a little rich you can close the fuel screw back to 1 turn open.
I wouldn't go playing with the needle yet, just let your son get use to the bike especially if stock.
If the snorkel and baffle are not there, well that will change the plan of attack.
Check things out and let us know how the bike is jetted and whether those parts are there or not.
There is no such thing as a dumb question here, so ask away if you are not sure about something.
It is cheaper and saves the frustration.
Neil - looks like there is a bit of Jim in me with that post - not that there is anything wrong with that.