How do you create a blur?

I’m trying to make a cinematic blur scene, where the camera comes into focus on a certain object. How can I do this?

You can do something like this by making a blurred transparent object that goes over the game in the UI (maybe better if its curved to the center of the screen). You can also control the blur by using the alpha of the Blurred UI object.

You can see this kinda done in my unfinished Winter Jam demo: (look at the UI layer)
https://flowlab.io/game/play/1307594

You could also use the blend block