You can't, if you're using the stock modem/router. You need to have a 3rd-party router (such as TP-Link, Tenda, ASUS, and many others) that has that feature.
gamit ng ibang router.. then doon mo sila lahat ipaconnect then change settings para malimit mo DL/UP speed nila. tapos yung main router mo pwede mo idisabled wifi nya.