In this video we analyze the pizza diameter data using a two-way ANOVA model implemented in PROC GLM. Here we see how to specify the model and how to use the SLICE option on the LSMEANS to test simple effects (also known as effect slices) in the presence of interaction. We discuss the importance of assessing interaction, including the nature of an interaction via an examination of an interaction plot, before deciding whether inference on main effects is appropriate.
The Module 7 lecture notes contain one more example (Example #9 in Mod7Examps.sas) of a two-way ANOVA in SAS. I encourage you to both watch this video and read through Example #9.