Seem to be very hard right now
Lucky you! When they're ripe, they'll smell really fragrant, and when you press one gently with the pad of your finger, the flesh should give a little. Should only take a couple of days at room temp to ripen.
Yes, you are lucky. We used to receive a box every winter and I can tell you they are delicious. Once they have ripened do put them in the fridge at that point - they can get overripe quickly too.