Using aggregate function in SPSS when performing multilevel analysis (Jan 2020)

This video demonstrates the use of the aggregate function in SPSS, which can be useful when performing multilevel analysis.A copy of the data file used in the video can be downloaded here:
Level 1 data file:

The example and files are based off Heck et al.'s (2014) presentation:

Aggregating data in SPSS,Aggregate data for multilevel analysis in SPSS,