This one wasn't too bad for me as I am pretty familiar with the ARIMA and ETS Tools.
-The hardest part for me was filtering off the years with only one session, using the Multi-Row Formula for and then bringing them back with a Union.
I had originally taken the average from Summer 1 to Summer 2 to Summer 1 vs. only taking averages for Summer 1's and Summer 2's, but that wasn't right. The Turbo Boost really helped as well as downloading the Alteryx Predictive Tools, which I hadn't downloaded before to save time on installing. One of the coolest steps I thought was using the Input tool to grab all the files in a single folder.