About change body.html and add or remove some of feature in meeting room

Hi, everybody.
I want to change interface of meeting room and change the body.html file but I can’t, and the file is empty for me. Please help me if the solution is exist.

You can add your customization in this empty body.html

Thanks, for your attention. This mean that if i change this file, my own website with all of change will display?

yes because this file is included to the main page on the server site.

Thanks a lot.

what about android app ?

No idea for the mobile side