How to make a trumpet bell

[micheus]

when I do that, nothing happens for "G" or "g". When I select one of the edges on the side of the cylinder, it selects to two edges of that polygon that touch the top and bottom rings...

By "polygon mode" I assume you mean the icon at the top of the workspace where I select faces..

you can do that by selection of the top face and then switch to edge mode.

I suggest you to watch some videos from the tutorials thread. You need a basic knoledgement about the interface and basics commands before we can explain things for you that you can understand.