Activating this trainer:
Press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.
Numpad 1: Unlimited Health
Numpad 2: No Blurred Vision
Numpad 3: Give Ammo
Numpad 4: Save Position
Numpad 5: Teleport to Saved Position
Numpad 1: Unlimited Health - toggle on and most things cannot kill you.
Numpad 2: No Blurred Vision - toggle on and the trainer will try to keep your vision back to normal as much as possible.
Numpad 3: Give Ammo - if you have a weapon that holds ammo, equip it then press this to give it the ammo shown in the trainer.
Numpad 4: Save Position - press to save your position to teleport.
Numpad 5: Teleport to Saved Position - press to teleport to saved position. After you press this, move slightly to complete the teleport.
Unlock more trainer options including updates from here - Hollow Trainer