Running express application's installed on the host

[userOne]

Running express application's installed on the host:
My host offered Mambo as a pre-loaded application in Plesk,

For one I need to turn on CGI support,?

And 2 setup a database because it would of grabbed one if one had been available.
How would it know which one to use so I wouldn't overwrite a database by accident if i'd had anything else setup then?

thanks.