iMac folder and Internet security

Ios newbie here

I have bought an iMac to replace one of my pcs.

I need to have folders which my children can't see and also want to restrict their Internet browsing to non-adult rated sites.

This was easy on windows 7 as I just gave my kids individual logins, and switched on parental control for them.

How can I do the same on iOS Lion ?

Many thanks in advance

John T said:

Easy! Just go to > System Preferences > Accounts. Then open separate accounts for whoever.

Click to expand...

Thanks
Will give it a try

What about children Internet control ?