Mobile App Downloads - Facebook Campaign

We are looking for a Facebook ad expert to help us with our mobile app download campaign. Our FB SDK is set up. You can guide us on event setup, if needed. We will try your service for a week and if we see any results we will go forward on a long-term basis. Currently, we ran ads for 2 weeks but didn't see a single app download. So looking for a reliable/knowledgeable expert to help us.