The dimple on the top of the pictured plate is a fitting marker.
Install a friction plate then fit the inner plate so that the dimple lines up with one of the arrows on the clutch hub.
Then fit each subsequent metal plate, with a friction plate in between obviously, so that each dimple is approximately 60 degrees round from the previous one in a clockwise direction.
The plates are designed like this to reduce clutch noise. Each plate is cut away round the dimple and this permits it to move outwards due to centrifugal force.
Oil up each plate before fitting