The upper mounting point utilizes a through-bolt (length depending on the diameter of the wood pole) and the diameter bolt would be 5/8”. The upper mounting point is a slot.
The two lower wings would utilize ½” lag screws.
Install the through-bolt hardware first, then hang the bracket onto the bolt so the slot is fully seated and tighten finger snug. Level the bracket and install the lag screw hardware.
Fully tighten the through-bolt after the lag screws have been installed.
Check all hardware a final time for tightness.