Using this Trainer:

Launch the trainer first, then launch the Game and then Press F1 at the Main Menu.

Listen for "Trainer Activated".

Press desired hotkey.

Options (Trainer):

Numpad 1: Infinite Health

Numpad 2: Infinite Shield

Numpad 3: Infinite Stamina / Flashlight

Numpad 4: No Reload

Numpad 5: Unlimited Ammo

Notes:

No Reload / Unlimited Ammo: While active you must shoo / reload before your ammo gets visually updated.