You do not need to be a qualified first aider to administer an AAI to a child in a medical emergency. 

Whether a first aider or not, if you work in an education setting, you should familiarise yourself with how to safely administer an AAI as this knowledge can save lives.

Instruction sheets for Jext and EpiPen AAIs can be found here: https://www.allergyschool.org.uk/resources/responding-to-an-allergy-emergency/