Activating this trainer:
Press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.
NumPad1: Infinite Fleet Hull
NumPad2: Infinite Fleet MP
NumPad3: Infinite Fleet Shield
NumPad4: Change Credits By 25000
Hull / MP / Shield:
You must have your fleet selected so the info panel of every ship is visible.
Unlock more trainer options including updates from here - Shallow Space Trainer