Go to the HTC mail app and add a Gmail account from there. You aren't very specific but I feel you are trying to add it into the GMail app? I don't think it works that way.
I have 2 Gmail accounts through the Gmail app and it still has the Add Account button at the bottom.
Sent from my Thunderbolt
ak2j said:Got it done. I was trying to add through the gmail app. I would get all the way to the finish tab & after clicking finish and going to the gmail app the second email was not there. After trying several times instead of clicking finish when I got to that screen I pressed the home button and it shows up in the gmail app and all is working well.