Item Reward
Item rewards give the player an item or a count of an item.
Example with count
For example here clicking the axe icon rewards two identical axes.

Rewarding with fluids or other custom data
The easiest way is to put the item with the fluids in your inventory.
For example we fill a small fluid tank from PneumaticCraft with lava.
When selecting for the item to reward the player with, we will click the compass to change the mode.

Then, we can select our fluid tank to give as a reward.
