What is Inset used for? like extrude i get what it's used for but inset seems like it just makes more lines?? I'm not sure i understand it.
It's like an extrude but inside the same face. Don't worry, it may seem alien right now, but you'll get the hang of it and find its usefulness in no time as you model more and more. It's hard to point it exactly what to use it for, but it's like how a window has 4 squares inside it, those are basically 4 insets.
It's used in different ways. One is to add additional geometry. Another is to avoid shading artifacts during rendering. For example the top and bottom of a cylinder which is by default an N-gon are difficult to bevel. So you can inset the N-gon face to have quads around the edge so that you can bevel that edge. Off course you could do it manually by deleting the face and then extrude the edge, escape out of the move and scale inwards then fill the empty space with a face again. As you can see insetting is faster and easier.