You can either do it via the ISP as Michael says or using the Synology router - I have a Synology router here.

What I do is enable the Parental Controls (time of day, site type restrictions) for specific devices - the tables my daughter uses. I then use OpenDNS as the network-wide DNS, so if she is using one of the adults' laptops there's still some level of protection. We also have Norton Family installed in all devices around the house. She knows to login on her account when using the laptops so this covers time limits and other things.