Add painting ability in my auto-landscape

Hi everyone! I made a auto-landscape following this 3h tutorial by CG Dealers: Create Massive World Landscape Auto Material - Unreal Engine 5 Complete Tutorial - YouTube

It looks great! I really like the result but I have an big issue: I need to be able to paint my landscape like I used to do with my basic landscape but I’ve no clue how to proceed. I left a comment to video but the author never replied.

This landscape also use functions. I’m still learning and even if I made those functions, I only followed the tutorial like a zombie. I’m not lazy at all, it’s just lot information to squeeze in my monkey brain.

Thank you for your time.

Anyone?