Opening the Dimitrescu Castle Gate will be among the first obstacles you encounter in Resident Evil Village. While it is not much of a puzzle it's still helpful to know how you can proceed to acquire the Demon Crest and the Maiden Crest required to open the Gate. Also, if you are having trouble solving the puzzle in special chambers you can read my guide.
First of all, the Dimitrescu castle gate itself is located it next to the Village's graveyard and on the right-hand side of it you will find the Village's Church.
How to Find the Maiden Crest
The Maiden Crest is very easy to find as from the castle gate, the next area you are probably going to visit is the church, which is the small house next to it. You will find the Maiden Crest upon an altar inside the chair, while next to the altar, you will find a map on a chair explaining to you that you will need the Maiden and Demon crests to open the gate and seek… safety(???) at the Dimitrescu castle. The map will reveal that the Demon Crest is located at Luiza's house.
How to Find the Demon Crest
Leaving the church and heading to the east will get you to a cornfield. Roaming around the crops, there are at least three lycans, although I remember killing around 5 or 6 eventually. Towards the end of the cornfield on your right, you will find a hut with Elena and her father (I think his name was Riccardo or something). These guys also want to go to Luiza's house, but the front gate is locked. If you jump out of the back window of the hut, you will find that the house's fence has collapsed a bit there, and you can climb from there to enter the house's yard. Then you can unlock the door for Elena and her father to enter.
There will follow a cut scene inside Luiza's house where the usual unpleasant Resident Evil surprise will make their appearance and the house will be set on fire. To leave the house you will have to find the truck key (which also contains a screwdriver) inside one of the kitchen drawers. Make sure to examine and rotate the truck key until you can open it and get the screwdriver.
After entering the truck you will have to bring a few walls down but then the fire catches up. Another cut scene follows and eventually you leave the house alone. As you jump down from the ramp, back to Luiza's house yard if you go to the right you will find a birdcage. You can now unlock the birdcage with the screwdriver and inside it you will find the Demon Crest.
Placing the Maiden and Demon Crests at the Castle Gate
Back to the castle door, you will have to examine the openings where you can place the two crests, and once upon placing each one of them, you will have to rotate them to align them and make them fit with the rest of the sculpture. Doing so will unlock the Dimitrescu castle gate. Now the fun begins… Good luck, Ethan!