You can create rules in the Advanced Settings of the router in the categories Scheduling and Parental Controls.
However, there are other routers which provide a far better interface for this task than do the Telus units, which are rather rudimentary. If you really want to fine tune your children's access, I suggest a device specifically designed for such tasks, leaving the Telus router for Optik TV if you have it.
Kids are pretty smart and have figured ways around parental controls for years. For what I suspect you're looking for, they will be useless.
If you just want to block all access to your kids' devices, and have the Actiontec T1200/2200/3200, you will want to look at Scheduling Access. It can be effective. They'll be able to connect to the wireless network in the house but nothing past that.
Just note that even this isn't 100% foolproof. Especially if your kids figure out your password or know their way around a router.
I've set everything up in advanced setting to restrict certain devices for certain time of the day. But the time the router blocks those devices aren't what I set up for. For example, I blocked my kid's iphones wifi access from 7-8am and 8pm-12am, but they are blocked at the wrong time. Any idea why? Thanks.