The Higgs boson is a particle. Specifically, it's the particle which mediates interactions with the Higgs field, in the same way that a photon is that particle which mediates interaction with the electromagnetic field.
A field is everywhere. Think of it like the surface of the water in your bath. If you perturb the surface of the water you get waves, and the waves will interact with other objects (you, the sides of the tub, your rubber duck). Now waves, in quantum mechanics, are also particles and vice versa. Bosons are excitations of a field; they are the particle-like aspect of the wave that you've made in the bathtub.
The Higgs field in particular is very much like the water in the bathtub. When you move through it you experience resistance, and that gives the effect of having inertia and mass. If you move your hand through the water, you produce a wave in the tub - an excitation of the Higgs field - but that wave is coupled to your hand and moves with it. If you suddenly release the energy involved in the movement of your hand - say by slamming it into the side of the tub - you'll produce another much larger wave which is independent of your movements, and that is what shows up as the Higgs boson.