If you have an active rental ad, you can use it to see all the potantial tenants who are looking for a rental like yours.
You can do so by signing in with your email address and password. Select "Find Lejer til valgte bolig" on your menu. You will then see a list of all those searching for a rental like yours, and you can contact them directly.
If you do not have a rental ad, you can make a search among potantial tenants by clicking "Search for tenants" under Rentals at the top of the BoligPortal front page. You can read more about this function here.