Use the designated hotkeys (usually Numpad 1–9) to toggle specific cheats.

To ensure the trainer works correctly, especially with different game versions on Steam or Uplay, follow these standard steps:

Some users report that Ubisoft's anti-cheat measures may cause crashes if cheats are activated too early; it is often recommended to wait until you are fully loaded into the world. Safety and Performance can anyone give me a working trainer? - Steam Community

Alt-tab out and run the trainer as an administrator.