abasel
created folder /etc/e-smith/templates-custom/opt/chilli/ and put the file there .... but what else do I do make the site use it?
See the template tutorial howto for guidance re expanding a specific template and restarting a specific service.
Immediately you can do
signal-event post-upgrade
signal-event reboot
which will expand the template and restart the service
Also I want to change some of the DB parameters but can't work out where to find them or how to access them
See the db command tutorial Howto for generic guidance.
This command
config show chilli
will show you what is set in the database, but to see what the default values are and to see what other db variables are possible, you will need to read the code in the template fragments for the coova-chilli contrib, in the location
/etc/e-smith/templates/opt/chilli/