Homebrew PCBs

I completed my schematic capture with the freeware version of EAGLE
and have begun board layout.   I am enjoying it, although I still have
to learn which layers correspond to the physical layers on the PCB.  
I am just keeping all my traces in the red layer.   I think that
corresponds to the copper trace side of the board.

Now I am trying to figure out how to make a copper-filled polygon in
the red layer.   I figured out how to make a closed polygonal figure
with the trace command.

But my polygons aren't filled.    They're hollow.   Or is that just
the way they look on the computer screen?  

I looked in the HELP.    Apparently I have to set the 'fill mode' to
SOLID for this operation.    How do I do that?   Also, how do I set
the line width for this operation?

Alan