They are required to pay you for all your time there including waiting for an assignment of work.Heres the site you can read and i'll post 3 hour rule.
Indemnity for reporting to work (less than 3 hours worked)
An employee who reports to work at the express request of his employer or in the normal course of his employment and who does not work or works fewer than 3 consecutive hours is entitled to an indemnity equal to 3 hours of pay at his regular wage.
The employee is entitled to the tips received during this period. If the provisions concerning overtime assure him of a greater amount, the employee will not benefit from the 3-hour indemnity for reporting to work, but rather the number of overtime hours increased by 50%.
This provision does not apply in the case of superior force (example: fire) or when the employee is hired for periods of less than 3 hours (example: certain ushers, school bus drivers, school crossing guards, etc