This page in our guide for Assassin's Creed: Odyssey contains information about the tomb found on Silver Islands which consist of Delos and Mykonos. Here, you can find a detailed walkthrough for the tomb as well as information on the weapons that can be found there.
Tomb of Brizo
Tomb's location: Delos, northern part of the island.
Walkthrough: Go inside and reach the end of the path. Soon, you will come across a passage blocked with vases (this place is presented in the picture above). Kill the snake and break the vases to reach the other side.
Keep following the path. You reach a passage with spiderwebs. Go through it and then jump down into the hole in the middle of the room. Kill 3 snakes. The animals are guarding a chest inside of which you can find Persian Warrior's Waistband.
A small room, with a snake in the center of it, is behind the chest. Kill the animal, go inside and hit the wall. This opens the passage to an Ancient Stele.