Motorola MG7315 User Manual page 46

Here is an example entry to block access to BadSite.com at all times:
Finally, make sure to check the Enable box, and click the Save button.
Click the + sign to add another site to block for this device:
Now you can add another site, for example WorseSite.com, to the Blacklist:
Remember to click Save.
Click the + sign again to add more sites if you like.
Click the Add button to configure a blacklist for another device, if you like.