Start watch compilation by selecting Terminal / Run Build Task...
Open the Run and Debug side menu, select Launch Extension from the debug configuration and hit run (F5)
Additionally you can also run Listen for Xdebug to debug the Language Server - but has to be run before the Language Server starts.
Note that the Phpactor Language Server currently only runs on Linux and macOS so if you are on Windows you might need to make use of WSL or a Linux VM combined with VSCode Remote.
Before submitting a PR also run npm run lint or Terminal / Run Tasks... / npm: lint.
Commands
phpactor.status: Show Phpactor's status
phpactor.reindex: Reindex the project.
phpactor.services.list: List Phpactor's currently running services.
phpactor.config.dump: Dump Phpactor's configuratoin to the log window.