After installing Everest, open the folder on your computer where Celeste is installed. You can do this in Olympus by clicking manage on the installation tab.

Then click browse on a particular celeste install.

You can also find the install location by following this guide: https://www.pcgamingwiki.com/wiki/Glossary:Game_data#Installation_folder

You should find a folder there called Mods. This is where your mod will need to be in order for Everest to find it.

Inside the Mods folder, create a new folder for your mod with a unique name.
ℹ️ For the purposes of this tutorial, the placeholder "MyExampleMod" will be used for the name of the mod.

Before continuing, verify that you have the "show file name extension setting" enabled. This is important because Windows might not save files with the right name otherwise.

Create a text file, then rename it to everest.yaml. Ensure that there is not an additional .txt extension by enabling file extensions in File Explorer:

Open the everest.yaml file in a text editor. There may be a warning that the file does not have an associated editor, select any text editor to use.

This file will be used to tell Everest the name and version of the mod, as well as what additional mods are required by it. It should look something like this:

- Name: MyExampleMod
  Version: 1.0.0
  Dependencies:
  - Name: Everest
    Version: 1.3471.0

All mods must include Everest as a dependency. Adding more mods as dependencies is as simple as adding more entries under the Everest dependency:

- Name: MyExampleMod
  Version: 1.0.0
  Dependencies:
  - Name: Everest
    Version: 1.3471.0
  - Name: SomeOtherMod
    Version: 2.4.7