Hi Mélodie,
I found the following tutorial that offers step-by-step guidance for adding categories to the front end of P2:
http://wpguru.co.uk/2013/10/how-to-add-drop-down-categories-to-automattics-p2-theme/
The first step to making big changes such as the above is generally to create a child theme.
However, things are a little trickier in your case as you’re already using a child theme of P2, Responsive P2.
As Responsive P2 hasn’t been updated in a couple of years and isn’t in the main WordPress.org repository, I recommend editing it to make the changes you want but keeping in mind that you will not be able to install any future updates released by the child theme’s author. The reason for this is that any direct edits you make to the child theme will be lost after installing an update.
If you make changes via your child theme instead of the main P2 theme, you’ll still be able to update the main P2 theme without losing any edits. This is important as updates may include security or bug fixes.
(In case you’d like a little more background to how child themes work, my colleague gives a good introduction and overview in this video.)
To follow the guidance in the tutorial I linked to, you will need to copy/paste the following files from P2 to your child theme’s directory:
- post-form.php
- inc/ajax.php
- js/p2.js
You can then edit them directly from your child theme.
Let me know how you get on with that or if you have any questions.
