How to make a fixed background?

I have a 4000x2000 layout,

and the view is 600x480,

so how can I add a 600x480 background that sticks in the back and if I move in the map (platformer) the background keeps the same always? (Just flat background)

Set paralex for the background layer to 0,0

here is a tutorial on Parallax:

scirra.com/tutorials/314/parallax-effect-with-4-layers-for-construct2-free-edition

The top layer can also be set to 0,0 for making a user interface that floats over the moving background.. (scores, radar, lifes, etc.)

Put the background image in a different layer. Set that layer to be the bottom one. Go to layer properties and set the parallax to 0,0.