In the case you want to build the Ad Manager Viewability Insights from source, you need to run the following Node.js commands within the directory to install the needed dependencies:
npm install
To get additional insights and logging message you need to use the following commands:
npm run build:dev
The compiled dev output will be in the dist folder.
To get the user version you need to use the following commands:
npm run build
The compiled prod output will be in the dist folder.