Here is the slides and the corresponding video @ 131:00.
# Generate the antlr target Java sources
bin/mill antlr4.genAntlr
# Generate for Intellij Idea
bin/mill mill.scalalib.GenIdea/idea
# Run tests for the example module
bin/mill example.test
If you have problem downloading the mill binary, you may try my mirror with md5 be1bc96003df4793e1892586d5c0fa7a.
Manually download it and save it to $HOME/.cache/mill/download.