First things first, you need to register a gmail account for open hap to work... then you need to log into that gmail account yourself and go through all the google setup like time zones etc etc. Once you can simply log into the mail account your about ready to get openhab using it. It may help while your logged in to try chatting to your regular account to be sure its authorised and works first.
############################# XMPP configuration ######################################
# The XMPP Proxyserver to use, e.g. "
gmail.com"
# the server port to use (optional, defaults to 5222)
xmpp:port=5222
# the username and password for the sending XMPP account
xmpp:password=XXXXXX
# a comma separated list of users that are allowed to use the XMPP console
###############################################################
Regards,
Jon