Sometimes, it's just easier to look at the pictures.
Use a magnetized medium Philip's screwdriver. 
Unplug the machine
Remove the cover, using a magnetized flat blade screwdriver, pop off the “C“ clip that holds the movement on.  It's at the upper left of the frame.  Remove the movement.  This exposes the motor.

Back the two motor screws off, about 3 complete turns.
Remove the wires that attach the motor to the wire block.
Jiggle the motor out, then move the mounting bracket over to the new motor and spring.
Reinstall.

Since it's already all apart, this would be a good time to oil the main shaft on the movement, and to change the ribbon.

This would also be a good time to change the ribbon...