I searched online for info about the church in English and about what the rituals were for the first of the month. Oddly, I came up empty. I found a few articles in Turkish, but even with Google translate they weren't very helpful. I posted on a Facebook group for foreign women living in Istanbul and got some helpful info that set me on my way. I'll share with you what I experienced, but since there was no literature available and the priest that did speak English asked me to make an appointment another time to speak with him, I'll just let you know what my friend and I experienced and hope that I intuited and understood everything correctly.
My friend Sayora and I took a bus from Harbiye to Taksim and then on to Unkapanı. You should get off at the Unkapanı bus stop and backtrack a bit to cross Atatürk Boulevard. You will find an underpass filled with shops and when you come out on the other side of the boulevard there is an ICM mall. Go straight on through the mall to the other side – you'll see the tiniest of mosques on your left and just proceed straight up the main street, Atlamataşı Cd. You'll walk a few blocks until you see an A – 101 supermarket and then, turn right (you will see a Turkcell across from the A – 101 supermarket - and you should proceed down this street.) You'll feel like you've stepped into an Ara Güler photograph of Istanbul in days gone by. It's charming, filled with vendors and old stores, but I was glad my friend was with me because there weren't very many women on the street. At the end of this cobblestone street, we came to a fork in the road and a kind man pointed out the church to us – a little up ahead on a slope across from another ICM market. Outside the church people were selling Turkish good luck charms, but I knew that inside the church they would be selling the keys needed for the ritual.
As soon as we passed the entrance, a woman came up to us offering us candy – we declined, but later we learned that if your wish had come true you were to come back to the church on the first of the next month and offer either cubes of sugar or some kind of sweets to the people who were visiting. Had we known, we would have accepted the offering and participated in celebrating the desire that had been fulfilled. We did later – even sucking on cubes of sugar as we waited for the tea man to bring us tea from the nearby shop.
The energy in the church was very powerful and Sayora and I rested with the other visitors in the garden/plaza area. We ordered tea from the local tea man (1 TL) and partook of the sweets and candies from the people whose wishes had been granted. I found out you're also supposed to return the key to the church when your wish has been fulfilled.
It was beautiful to see how many people offered us sweets and had returned to give thanks and to share their happiness. It was a lovely beginning to a new month and a new way of being. I hope to return soon with sweet thanks giving of my own.
Unkapanı Atatürk Bulvarı
Vefa Katip Çelebi Caddesi
Google maps has it at: 41°01'06.8"N 28°57'33.2"E