@Kate , Thanks for posting this good question. Hope you had a good weekend!
Firstly, much appreciate your positive feedback for Soumi-MSFT's support and document author, we are glad to hear that and have shared the feedback :)
Most Angular apps will actually put the built application in "dist/<name of angular app>" and could be due the trailing '/' (As discussion here)
Just to highlight/to review:
app_location
-Location of your application code. For example, enter / if your application source code is at the root of the repository, or /app if your application code is in a directory called app.
app_artifact_location
- Location of the build output directory relative to the app_location. For example, if your application source code is located at /app, and the build script outputs files to the /app/build folder, then set build as the app_artifact_location value.