Computer Science Homework Help

I have tried using the QOS in the dd-wrt firmware and it did not work. I also tried generating a script and update my firewall settings and that did not work either. I am in need of some help and guidance getting this done. 

My aim is to have a low bandwidth that’s good enough for basic internet browsing, email, social apps( like what’s app) while at the same time preventing the heavy download from streaming videos such as YouTube videos, and video games. Low enough so streaming videos will play choppy to deter users from trying to watch videos from the hotspot. I do not want to block you tube it in all entirety. 

Thank you.

Step by step instruction to achieve this with the dd-wrt software on linksys AC1200