Installation guide here:
https://www.uk-plumbing.com/brochure/potterton/ep2installationinstructions.pdf
It's described as a direct replacement so it'd be a case of remove the old, clip on the new and configure in accordance with the instructions.
User's guide here:
https://www.freeboilermanuals.com/assets/User_Manuals/Potterton/ep2userinstructions.pdf
Also: I thought I'd posted this before aas it outlines some of the pitfalls and how to address them:
https://community.screwfix.com/threads/replacing-a-potterton-ep3002-programmer.177406/
Edjdj, August 2022