• Everest:link: for loading and playing custom maps and other mods.
• Lönn:link: for creating maps.
• Any text editor
• Any program that can create .zip archive files (7zip:link: is a free and reliable option).
• (Optional) FMOD Studio Version 1🔗 for adding custom music.
• (Optional) Any art program suitable for pixel art (LibreSprite:link: is a good free option).

After installing Everest, open the folder on your computer where Celeste is installed. This page has some information on how to find it if you are unsure: 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.

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

Finally, create the following folders inside your mod folder, next to the everest.yaml file:

Celeste
- Mods
  - MyExampleMod
    - Maps
      - MyName
        - MyExampleMod

⚠️ "MyExampleMod" and "MyName" must be replaced with the name of your mod and your name/nickname

Creating and editing your map happens in Lönn:link:.

⚠️ Every playable room must contain at least one Player Spawn Point entity.

If you have set up the folders for your map correctly (see Mod Setup), your map should be playable right away.

From the Chapter Selection Screen (where you can navigate between different chapters), press the Up and Down arrows to switch between modded map campaigns, or press Tab to open a search menu.

ℹ️ It is recommended to enable Debug Mode and use the ~DEBUG~ save file (available from the main menu with Debug Mode enabled) when testing your map.

Custom entites can be added to the game using "Helper" mods. Many helper mods are already available for use on GameBanana:link:. A full list of all currently registered custom entites can be found in the Custom Entity Catalog:link:.

To use a helper mod in your map, make sure you have it installed, reload Lönn, and any custom entities or triggers should automatically be loaded by the editor.

⚠️ Keep track of the helper mods you use and add them to your everest.yaml file. This will make sure that they are installed for anyone who wants to play your map:

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

When you start testing out your map, you may notice that the name is set to something like {MyName_MyMapName_MyMapFileName}. To change this and all of the other placeholders, we need a "Dialog File".

Dialog Files are all placed in a Dialog folder, and are text files named with the language they apply to. For English translations, that means creating a file called English.txt:

Celeste
- Mods
  - MyExampleMod
    - Dialog
      - English.txt

Within the dialog file, you can assign any text value to a "Dialog Key".
⚠️ Dialog Keys can only contain Alphanumeric characters (A-Z and 0-9) and underscores (_). Any other special characters, including spaces, should be replaced with underscores when used in a Dialog Key.

For example:

• MyName/MyExampleMod becomes MyName_MyExampleMod
• Words with spaces becomes Words_with_spaces

As a general rule, whenever there is text in-game surrounded by braces ({}) or square brackets ([]) it can be added to the Dialog File as a Dialog Key.

For example, if your map name is displayed as {MyName_MyExampleMod_MyMapName} it can be customized like this:

MyName_MyExampleMod_MyMapName= My Map Name

⚠️ There cannot be any whitespace between the Dialog Key and the equals sign (=).

The process for adding custom graphics to your map depends on what those graphics are for. Following are some common scenarios:

If you have not already, add the following folders to your mod folder:

Celeste
- Mods
  - MyExampleMod
    - Graphics
      - Atlases
        - Gameplay

Within the Gameplay folder, custom decals should go in a decals folder, and stylegrounds should go in a bgs folder.

ℹ️ When adding any custom assets to your map, make sure to include your name/nickname and the name of your mod in the path. This helps prevent conflicts with other mods.
In this case, decals would go in decals/MyName/MyExampleMod, and stylegrounds in bgs/MyName/MyExampleMod, with "MyName" and "MyExampleMod" replaced with your name/nickname and the name of the mod.

Entities can be given custom textures in a few ways, which are detailed in the Reskinning Entities Guide.

Many parts of the map selection panel can be customized for your mod. These textures will all go in a Gui folder in the Atlases folder:

Celeste
- Mods
  - MyExampleMod
    - Graphics
      - Atlases
        - Gui

A full reference for the UI elements that can be customized is available in the UI Customization Guide.