My speedometer is not working

Speedos are either mechanical (old and I don't know when your model changed) of electrical.

For mechanical, the shaft is connected to a port on the transmission and run up to the back of the speedo.

For electrical, there is a sensor connected to the transmission housing. The wiring then runs to the speedo, either directly of via an ECU.

In either case, if it is not working something is open. Either the shaft has become disconnected, or a connector become loose or disconnected, a wire broken, or the speedo or sensor is malfunctioning.

1st - determine what type it is. Then proceed to check the possibilities.

2nd - for electrical, start with connectors and wires. If there is an OBD connector, you can see if the ECU is reporting a speed using an adapter and an app like Torque. If it is, then the ECU to speed circuit is suspect. If it isn't, then the Sensor to ECU circuit is suspect.