Guess it sort of depends on what experience you have with tractors as to how many questions should be asked. But it's a good idea to start now writing them down so when the time comes you won't forget to ask them. Also don't feel in any way shape or form that a question is stupid. The only stupid question is the one that you didn't ask.
So here are a few that might help you out.
How to remove and reinstall the loader.
How the loader works
How the three point works.
Can you control how fast the three point lowers.
Where the dipsticks are. Also other locations to check fluids.
How the fourwheel drive works, what to do if it's hard to get in and out of fourwheel drive.
How to install the mower.
What kind of oils does it require.
How the pto works.
Any lever or pedal that you see also ask about.
Of course strarting/stoping the tractor and warm up cool down times.
That is a few off the top of my head. Don't be in a rush take a few minutes to learn the new tractor you will be alot better off in the long run.
Gordon