The Driver is used to power the lights, it is quite simple to work out which driver to use but two rules will help you get it right.
1. Never overload the driver - if you connect up too many lights on the wrong sized driver it will fail.
2. Always leave a little spare room on the driver - they prefer to be just below the maximum.
So to work it out we are going to calculate the total draw of all the lights - as shown below...
This example shows a more complex system