what you have to do is when you graphically open your router by typing your default gateway Ip address in your browser. it is something like 192.168.x.x (x= any no. between 1 to 255)
you will prompt for username and password.
Some of the hardware providers will give default user name and password on the router it self or just check your manual if u dont know your password.
Now when u opne your router you must look for something like connetion timing or schedule. where you can select start time and end time and days too. just navigate through your router's page.
If you have any further queries plase feel free to contact