You do not have to do anything to make the block. It does it automatically. I will give it thick collision-geometry, and any impact on it will not damage the user. The player with the shield will be able to extend it towards the direction of the incoming attack to block it, so the player takes no damage.
_________________
I am sorry to report I have destabilized the relative speed of some photons, which caused an immediate singularity to form. Then, the singularity pulled itself away from the space-time continuum and destroyed a local trailer park. I hope my insurance covers this.