In order to create a query you have to create or retrieve the id of the object (a database) you want to query from.
Considering you have created a $silverpop (new EngagePod) with login credentials and server number (https://ictknowledge.net/engagepod-php-php-library-silverpop/);
You can use GetList call to extract a list of databases
$dbs = $silverpop->getLists(2, false)
Then you can pass the query to your database, the following example returns all the lines with the email address equal to the one given:
retrieve_adr is the name of the query that will be created
$list_id is the variable where the database id is stored
$list_id_res = $this->silverpop->createQuery('retrieve_adr', $list_id, NULL, array(
'TYPE' => 'TE',
'COLUMN_NAME' => 'Email',
'OPERATORS' => '=',
'VALUES' => 'firstname.lastname@example.org'