Newbie question on how to fix some faces and vertexes

Hello! I’ve got a very beginner question here on how to fix some geometry. I’m following some steps and I’m trying to make all of these “buttons” match each other.

I noticed that the button in the middle on the left has a strange edge to it that none of the other have.

I’ve tried selecting it and resetting the normals which didn’t work. I’ve tried smoothing it out which also didn’t work so I’m not sure what I did wrong or different that it would end up like this, or how I should go about fixing some geometry errors like this.

Any suggestions?

Thanks very much!

Remove any internal faces
Remove double vertices ]
Ensure you have a continuous mesh (no disconnected faces or stray edges)
Recalculate normals (Ctrl+N)
Turn on face normal display (properties panel under Mesh Display) and manually flip selected faces (W / Flip Normals)

You have not supplied any .blend file for review so cannot give a specific solution, you’ll have to do the detective work yourself

Hi, sorry, I’m a bit new to this, I tried all of those things and at least what I tried didn’t see to work. I tried to upload the Blend file to the forum but it didn’t want to work, so at least I have this link for it.