The app has a lot of cool skins for Minecraft. You can see the skins by means of a pre visualization in the app.

The app has a tutorial to guide you installing the skins.

Select the desired skin, by "most downloaded", that way you can choose the best outfit for your School character.

DISCLAIMER:
This is an unofficial application for Minecraft Pocket Edition. This application is not affiliated in any way with Mojang AB. The Minecraft Name, the Minecraft Brand and the Minecraft Assets are all property of Mojang AB or their respectful owner. All rights reserved. In accordance with http://account.mojang.com/documents/brand_guidelines