AC87U - how to block facebook per specific client?

Hi everyone,

I'm using Asuswrt-merlin v 380.57_0 on my AC87U. I need to be able to block Facebook, specifically on my 11 year old's Tablet. So far I can only see how to do this globally which is no good.

If you could let me know how I can do this....with the specific tabs and settings to access....in very simple terms please - I would be very grateful!

Thanks !