What is the most logical next event?

How to hang a gate
Dig a hole at least 3 feet (or 1 meter) deep using a post hole digger.
Place one of the posts into its hole and while holding it as level as you can, pour dry concrete into the hole until it is half filled.
Pour in roughly 5 inches (or 12. 7 centimeters) of water and let the mix soak for a minute or two.

Select from:
(I) Fill the hole to about 5 inches (or 12. 7 centimeters) from the top with more of the dry mix, adding another 5 inches (or 12.
(II) Properly suspend the gate into the hole and allow it to soak. Check the gate's plastic surface for rot and discoloration.
(III) Add some more warm water and continue to drip concrete into the hole. Pour out the water and then connect to another post.
(IV) Pour another post hole that is slightly shallower. Set your gate into its hole Fill the other hole with the loose concrete and sand.
(I)