Hi Stephen,
I always think it is best to start with one of the examples provided and then edit it to your needs. This way you can be sure that most things are setup correctly initially, then you can keep performing regular compilation to make sure you have not introduced anything.
I'd suggest looking at the GPIO Interrupt, SPI Loopback or UART examples.
You can find these examples by following the below steps.
1) Make sure you have installed TI-RTOS and the latest version of CCS
2) Select TI Resource Explorer from the View menu within CCS
3) Select TI-RTOS from the Packages drop down
4) Expand ARM - Expand Tiva C Series - Expand Tiva TM4C123GH6PM - Expand Example Projects
5) Select the example you would like to use or review
6) Follow the 4 steps present to install and build the example
Glenn.