How can I use webcam on RPi to collect streaming video data for WebRTC streaming?

[edwardchang0112]

I tried to follow the steps

On my RPi 3 (buster)

sudo apt update
sudo apt full-upgrade

sudo dpkg -i rws_0.74.1_armhf.deb

sudo systemctl start rws

then I go to http://local_ip:8889/native-peerconnection/ on web browser

On my another computer under the same network
I go to http://local_ip:8889/np2 on web browser

I can see the simple UI on the above two web browser, but I cannot make it stream my USB Webcam data?

How to do this? How the modify the config for streaming the data from USB Webcam?
Thanks in advance!