I found the Luna's Slice Theorem very Technical. It will be helpful if someone illustrates the geometry involved in the theorem. Also why this theorem so useful?
This is Luna's Slice theorem from a lecture note of Jean-Mac Drezet Luna's Slice Theorem and applications- Lecture note by Jean Mac Drezet And this is the Version of Luna's theorem when the point x is smooth-
Also I will use the opportunity to attract attention to one of another question where I asked the meaning of a topological slice of a point- Slice of a point of a topological space
Is there any other resource to know more about Luna's Slice Theorem?