Is it hydrostatic? 4WD? Try driving it in all speeds, forward and backward, try engaging from 2 to 4 WD, run it offroad and turn in 4WD to listen for drive strain/damaged 4WD components. Before you start it check hydraulic fluid, look at the basics, check for oil leaks, check oil level, radiator leaks etc.
Then try the hydraulics, 3 PT raise/lower, engaging the PTO's etc.
It is a fairly new machine so chances are it does not have any problems.