Sphere cast thing help please!!!!

I want to do a sphere cast like seen on this video to make a grenade: Intruder Series 002 Concussion Grenades - YouTube
but I have no ideia how to do that thing, someone help please, javascript prefered btw

They are using Physics.OverlapSphere() to detect colliders within a certain radius of where the grenade explodes, then they are using Rigidbody.AddExplosionForce() to toss the people around. There is a example script using both in the Rigidbody.AddExplosiveForce() reference page.

The other thing they are doing on the video is to Raycast from the explosion point to the bounding box of the player to see if the player is exposed to the blast or hidden behind a wall. I suggest you get the explosions working first, then go back and add the raycasting.