Is there nobody in your organisation who could guide you. Hope the agency was not started yesterday. Even then, before starting a business, you or the owner or whosoever is the shareholder or investor should have done some ground work before starting the business. Your question is like asking how to swim, after getting into the river. There are job portals available where you make payment to get access. People sell database of candidates... There are so many options available, but first do the ground work before asking such questions here ! CiteHR or the people here cannot provide candidates !
Best wishes