It is super easy, as you can see on the video. You can use the pre-installed build orders or design your own. It is also transparent to mouse clicks, so that it does not interfere with your game. It shows the build order in a more compact format (one step at a time) and is well suited when playing without a second screen. The build order overlay is purely manual and basically provides the same features as a pdf reader or post-its on the screens.
Instructions are provided in this video and in the Readme.
Just download the zip and run the executable in it (you do not need to launch the game to run the app). For those interested, I developed this overlay to display build orders (29 already included from Hera's pdf and YouTube videos) and match data (player Elo, rank, win rate.) while playing.
