Sorry, I had thought I sent you a response on friday, but I guess it didn't get submitted.
There are some pretty helpful members on the forum, so if they provide a satisfactory answer, we'll leave it.
As for the setting up of the datasource connection, you would want to follow the second part of the document, starting with this line:
To create a MySQL connection for PHP:
I should have clarified that. It looks like that document was created for an old version of eCart. Here is a more clear tutorial on how to set up the database connection: