G2-manifolds are 7-dimensional, Ricci-flat spaces, and G2-instantons are certain interesting principal bundle connections on them. I will begin by explaining the definitions of these things—no prior knowledge of G2 needed! Ignoring all analysis, I will then explain one example of a G2-instanton constructed by me on a G2-manifold constructed by Joyce-Karigiannis. The construction is a gluing construction, gluing together a stable bundle on a K3 surface with some other standard building blocks. This is an example of a more general gluing construction, and time permitting I will state that more general gluing theorem.