Okay. For posterity, here is my solution in step by step format:
1: I created a material, set the material doman to “User Interface”, and set the blending mode to “Masked” (to get rid of the key background).
2: I added in the UV texture and hooked up a Flipbook node.
3: I attached constants to number of rows and number of columns
4: I attached the following equation to the Animation Phase node: “Time” Input Data * material constant (in my case, 0.3).
The most important thing to remember is that the material expression constant is roughly equal to one hundredth of FPS. For example 30 frames per second would be 0.3.