Does the motor turn over? Are there any sounds or indications that the starting sequence has been initiated? If you could provide any additional information... There are a lot of folks that can provide some insights... It would also help to narrow down what the battery voltage is and how you determined it...
If I had the issue I will be wanting to see if I had the proper voltage to the solenoid.. and if I had the proper voltage to the starter... There are a couple of steps to get there.
I have always been of the school eliminate the simple things first. Usually the simple thing is low battery voltage... Then solenoid, starter motor, ignition switch...
You will need a multimeter and a way (usually a wire) to bypass the ignition switch and energize the starter solenoid....
JohnnyT