First off Welcome man.
First thing i would do is drain the coolant then flip the bike on its side (clutch facing up level) and pull the clutch cover off and check to see if the eccentric screw sheared off or if you bent your shift shaft, or maybe your shift star come loose or fell off and got jammed up.
Also check to see if the basket is still intact and not broken as well as the gears behind it, basically look at everything in there to see if anything is bent, broken, really worn out or fell off.
Worts case, it could be that you bent a shift fork or stripped some trans gears inside, you will need to split the cases to check. (not even a big deal though)
But check the first things at the top first, proly something really easy so have a look see and check back.