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: Add Credits
Numpad 2: Unlimited Shields
Numpad 3: Unlimited Hull
Numpad 4: Unlimited Fuel
Numpad 5: Unlimited Energy
Numpad 6: Unlimited Heat
Numpad 1: Add Credits - while in ship and you can see your credits, press this to add more.
Make sure you have at least ONE pilot created and you are in the ship and flying around, then engage these options. These options are for the main ship you are controlling.
Unlock more trainer options including updates from here - Endless Sky Trainer