Run debug.ps1 or debug.sh (depending on your system) to set up the project for development.
You can then run the binary located at ./build/debug/lowlevelgame.exe or ./build/debug/lowlevelgame (depending on your system).
Release builds are similar, with the scripts release.ps1 and release.sh, and their executable in build/release/ rather than build/debug/.
Figure them out yourself