Couples reach you in two main ways. They can message you directly from your profile, and once you are logged in you will see and reply to those messages there. On the paid plans, they can also request and manage bookings with you through the site, which keeps enquiries in one place instead of scattered across your phone.
The one habit that wins the most work is replying quickly. Couples usually message a few vendors at once, and the one who comes back first with a warm, clear answer often gets the job. Keep an eye on your messages, especially in the busy wedding season.