Is there a quick guide for setting up DIC on a PS4 controller?

best bet i would imagine is using joytokey and then binding the desired button to the key you would have set in the "secondary input" tab.

Thank you! I'll give that a try. Just to confirm, the idea is to bind, for instance, L2 to the left/right keys of the keyboard?

yeah that's it

You can try also xpadder. Im using it all my career :)