I cannot figure out how to change the mood of my space and the answer here does not work. also what I am doing

I am an adult and you must have to be a child to understand this! How do you change the box that says extendended network to something else? Please be easy on me I am not good at this! And the mood.....I cannot figure out how to change the mood of my space and the answer here does not work. also what I am doing
I can't find a box that says extendended.