My question is about how can i add a post process effects such as changing the color or adding blur to main camera whenever i step in to a trigger. i want the screen to turn red for a few seconds to indicate the player is taking damage.
You can create a post process volume that covers the trigger and has the effect you like. Then in level blueprint you can manipulate that pp volume’s blend weight with a Timeline if you want the effect to show up in a pulsing manner or for a limited time.