I have done it on a TC-321.
You first need to release the coupling to the motor. This is done through a hole on the right side of the spindle. Release the clamping screw of the lower coupling. Then remove the motor from the spindle. After that remove the screws at the spindle head. Use a piece of wood and a small hammer and you'll be able to push the spindle out of the housing. This is done through the motor area. The Z-axis must be high enough for removing the spindle out of the housing.
Be shure to get the right bearings. Then replace the bearings (direction is important) and check that the drawen lines of two bearings will show a "V".
Very important is to fill ~30% of the bearings with glue (not more!!!). Then attach the bearing screw. This must be done with the right torque which I don't know for your spindle. Maybe you have to try out.
After that you can put the spindle back into the machine. If you are ready you'll have to setup the orientation. This can be done through the machine paramters.
Sorry for my english...