Try installing the needle at the 30MPH position, and the needle should rotate back to or close to 0 MPH. Keep trying different MPH till the MPH rotates back to 0 MPH
Another way with the engine running.
You can try to install the needle while the car is running. Pull the emergency brake and put the trans in D. With the instrument cover off, slip the needle back on.
These steps should get the speedo working, but you need to check the accuracy.