This message is here to provide a few more informations about how to properly install this mod, and what the issue is when an obvious problem arises.

First, switch your game version to the gateofhorn beta version. For that, go in your games library, right click on Cultist Simulator > Betas > pick gateofhorn. This should trigger a short download.

Then, on the workshop, subscribe to Codex, GHIRBI, The Roost Machine, and Mariner.

Then, start the game, and enable Codex, GHIRBI The Roost Machine (you might need).

Restart the game. Enable Mariner.

Mariner should now be available as a legacy in the Sixth History menu.

It is mandatory for The Roost Machine to be enabled before you boot up the game to enable Mariner.

Q: When I do the very first action "Coming Back to Port", the game stays stuck and crazy stuff starts happening!
A: You forgot to subscribe to and enable AchieveIntegrations. (1.0.7 and older)

Q: My game crashes on startup!
A: Either you're not on the gateofhorn beta branch of the game, or you didn't enable some mod (probably The Roost Machine).

Q: My game crashes on startup, how can I clear it so all mods are disabled and I can go back to the main menu and start the installation process again?
A: Go into the saves folder of the game. On Windows, it is located in C:\Users\{your user}\AppData\LocalLow\Weather Factory\Cultist Simulator. In there, delete the file named mods (or open it in a text editor and clear its content). It will disable all mods and you should be able to start the game again.

If you wish to also purge your save file (some crashes can come from saves relying on now-disabled mods), simply delete the save.json file in this same folder.