Why does my extruding not work like this? This is what mine looks like. Here is what I would like it to look like:

I cannot figure out why the edges of mine are not expanding like in the tutorial I'm following. I'd appreciate some suggestions.
You have overlapping vertices, it messes up your extrusion, go in Edit mode, select all and press AltM > Merge by Distance.

The threshold in the Operator box should be enough.