Documentation/Usage Guides/Sideloading Guides/ADB-Sideloading.md
adb pair <IP:port> to pair ADB with WSA.adb connect <IP:port> to connect WSA with ADB.Once this is done, use command adb devices to make sure that WSA is connected.
Now you can install any app you want, but I personally suggest installing a web browser and a file manager first.
adb install <file path> to install the APK.You can now open the web browser you installed in Android, and download and install Aurora Store like you do on any Android device - normally sideloading APK without using ADB.