To create a model for the table members in your database, create the file application/classes/model/member.php with the following syntax:
class Model_Member extends ORM
{
// ...
}
(this should provide more examples)
If you wish to change the database table that a model uses, just override the $_table_name variable like this:
protected $_table_name = 'strange_tablename';
ORM assumes each model (and database table) has an id column that is indexed and unique. If your primary key column isn't named id, that's fine - just override the $_primary_key variable like this:
protected $_primary_key = 'strange_pkey';
For each model, you can define which database configuration ORM will run queries on. If you override the $_db_group variable in your model, ORM will connect to that database. Example:
protected $_db_group = 'alternate';