Collision not happening

I am new to unity.I am following Will Goldstone’s book Unity 3.x Game Development Essentials book.In a scene I have made few powercells.When I am trying to navigate using First Person Controller ,I “pass through” these power cells.Both of them have got rigid body attached to them.What could be the issue

You must attach a collider object and then ensure the “IsTrigger” checkbox is indeed checked.

This will convert your collider from a barrier that is like a force field around the object disallowing things through it, to one that does allow things to pass through.

You may have to attach a further collider that is not a trigger to the same gameobject to ensure it has collision with the ground(terrain). however, you could also simply check the rigidbody to be “IsKinematic”, removing gravity from it by doing so and allowing the objects to be effectively static where ever they are being placed in your scene.

hope that helps you soemwhat buddy, same thing happened to me when I got that book.
Its an Amazing Book for beginning your game dev journey IMHO.