I'm sorry for the ambiguity of this post but I was left with quite a mess it seems. I recently came on to this job and there was a deployment of about 120 Windows 8 tablets to 4 different schools. I don't know who created the image or how they were planning to manage the tablets and I am unable to even find out who it was.
It is set up with an admin account which is also a Microsoft account. There is also a local student account on each machine. The admin account is set as a parent account through family and safety center.
The goal of these machines was to have students log in and use some pre-installed educational apps. However, when the student logs in to the local student account, the apps have an (X) on them and if I try to open it, it will bring me to the MS Store and a dialog box appears saying the app needs to be repaired. I click repair, I am prompted to log in with a Microsoft account and I log in with the admin account. This does repair the app and makes all other pre-installed apps work correctly. This only worked up to a point though. Eventually I got an error message that the Microsoft account can only be linked to 81 PCs.
I have tried creating a new Microsoft account that is also set as a parent account, but when I use that account to login on the repair screen, nothing happens.
I sadly have no idea how I should have these tablets set up. I have tried creating a new account which has been designated as an adult account in family and safety but that did not work.
I think this question is going to be far outside the scope of the site because you're asking for a hugely broad answer.
Right now, I will say that it sounds like someone's tried to bodge using home tools (shared accounts, parental controls) for an enterprise deployment situation and that never ends well.
I suggest you look at a Mobile Device Management (MDM) solution. For Windows in an educational environment, I suggest starting with Microsoft's Windows Intune, even though I'm not big fan myself.
This will allow you to manage the tablet "environment" and deploy apps in a much more controlled and robust way than fiddling around with parental/admin accounts locally on each tablet, not to mention doing a far better job of locking the systems down so that they are secure and safeguarding obligations can more easily be met.
A good MDM deployment will even allow you to do things like wipe devices remotely if they're stolen, deploy and remove apps, re-image devices on demand, etc.