Activating this trainer:

Press F1 at main menu.

Listen for 'Trainer Activated'.

Press desired hotkey. All hotkeys can be changed on the trainer.

Trainer Options:

Numpad 1: Set Health

Numpad 2: Set Stamina

Numpad 3: Set Hunger

Numpad 4: Set Thirst

Numpad 5: Set Fatigue

Numpad 6: Set Inventory Space

Notes:

Numpad 1: Set Health - once you are in the game and can move about, press TAB to see the tab showing the current value, then press the option key to set it to the value shown in the trainer.

Numpad 2: Set Stamina - once you are in the game and can move about, press TAB to see the tab showing the current value, then press the option key to set it to the value shown in the trainer.

Numpad 3: Set Hunger - once you are in the game and can move about, press TAB to see the tab showing the current value, then press the option key to set it to the value shown in the trainer.

Numpad 4: Set Thirst - once you are in the game and can move about, press TAB to see the tab showing the current value, then press the option key to set it to the value shown in the trainer.

Numpad 5: Set Fatigue - once you are in the game and can move about, press TAB to see the tab showing the current value, then press the option key to set it to the value shown in the trainer.

Numpad 6: Set Inventory Space - press this to set the inventory space to the value shown in the trainer.  The max is likely 36.