Simple by design.
A Priest is a purpose-built fish dispatch tool. Use it decisively, maintain control of the fish, and follow local regulations and accepted humane-dispatch practices for the species you keep.

Four deliberate steps.
Secure the fish
Keep the fish controlled on a stable surface and keep fingers, hooks, and tackle clear of the strike area.
Identify the proper strike point
Target the top of the head immediately above and slightly behind the eyes, adjusting for the anatomy of the species.
Use one firm, controlled strike
The goal is immediate stunning or dispatch, not repeated light blows. Verify insensibility and follow accepted fish-handling practice as needed.
Rinse, dry, and stow
Rinse off salt, blood, slime, and debris. Dry the Priest and leather before extended storage.
Use only as intended.
The Last Rites Priest is designed for lawful fish dispatch. It is not a toy, club for general striking, pry bar, hammer, or substitute for other tools. Keep it secured when not in use and away from children.