Pull the cover plate on the lower rear of the blower (usually have to remove 6-8 screws), it should let you get to the internals on the back of the machine, around the axle(s). Most of these are friction drive, with a rubber wheel on a steel plate, pretty simple operation. You should be able to figure out any hangups/issues once you have that cover plate off.

There are a couple snowblower forums on the web where you might get more specific help (opeonthenet, abbysguide, etc.). Be sure to have your model number handy when posting for help.

Bout 5 years ago, whilst riding around on "trash/garbage night". i espied a Craftsman tracked snow thrower reposing along side the pile! So, i enquired at the house. They said to take it, and helped me load it!
So, being that i am an inveterate trash heap follower, i took it home.
With some TLC, i got it to run well. Couldn't find anything wrong with it, except for a bad case of neglect. I then sold it to a friend who has a long driveway, and is happy with it. Ya never know how the fickle finger of fate will knock on yer door.
RJ