monitoring traffic at router

[#1]

Hi,
I am beginning to get concerned about my children making inappropriate use of the internet and would like to do some monitoring.  As they have iPad, smartphone and PC  my idea would be to monitor traffic at the router.
Would this be as simple as looking at the router log files (how do I do that?) or do I need some software?
I have a plusnet provided Thomson router.
Thanks for any help.

[#2]

I don't know what the thomson can do off the top of my head, but opendns do a parental control product which could give you want you need,

[#3]

This software is not Router dependant http://www.softperfect.com/products/networx/ I used it a long while ago and will probably use it again.
As far I can tell it will log user/usage and that may be the sort of monitoring you are talking about but as for parental controls......................I have a feeling my Netgear has some fine tuning possible to block sites but not sure that is per user or global???
HTH maybe

[#4]

The OpenDNS Parental Controls solution blocks access to sites rather than monitoring IIRC. I think you have to pay to get stats. However the free FamilyShield offering is dead easy to set up. You just change the DNS servers on your router as described at https://www.opendns.com/home-solutions/parental-controls/.