On the solenoid, the battery cable connects to one of the large posts, the other large post connects to the starter. The small post with the tab is the circuit that energizes the solenoid that makes the starter rotate and engage the engine.
Touch a wire, piece of metal, or screwdriver between the solenoid post where the battery cable connects and the small post with a single wire. The small post sometimes has an "S" for start. It causes the solenoid to engage the starter. That bypasses all the wiring to and from the control console.
If the starter works then the battery cable and batteries are ok and the problem is between the tab and the control console. If the solenoid clicks or the starter hums, then you need to replace the starter. Most auto parts stores will check the starter for free.
If you want to check out the solenoid further, touch a screwdriver across the 2 large posts. There will be sparks. If the starter turns, and it didn't before, then it's the solenoid.