(doc) how to create new page

README.md

@@ -134,6 +134,11 @@ Now let's use the fix option of ESLint.
 
 Our file gets formatted the same way Prettier did.
 
+## How to create new page
+
+You can find [a documentation under the doc folder](doc/how_to_create_new_page.md).
+
+
 ## Gatsby Starter Catalyst
 
 Basic starter that could be used as a barebones starting point for building a finished website. Implements `gatsby-theme-catalyst-core`, `gatsby-theme-catalyst-header-top`, and `gatsby-theme-catalyst-footer`.

doc/how_to_create_new_page.md

+# How to create new page ?
+
+We have two principals steps to make for create a new page in this Gatsby Theme. We can also create a new page in a sub menu.
+
+## First step
+
+This theme is configure to work by default with a template page files under `content/pages/`.
+
+So, we need to create a file in `content/pages/` with the `.mdx` extention. This file will become the new page.
+
+## Second step
+
+We have to go in `gatsby-config.js` file.
+Next, in the siteMetada, we have to add or rename the menuLinks values.
+
+### name value 
+
+`name` is the value that will emerge in the site header
+
+### link value
+
+`link` correspond to the name's page of the file we had create in the first step, in the template page `content/pages/...`
+
+### type value
+
+`type` can be :
+  - `internal` : use to create a link to an other page of the site.
+  - `anchor` : use for a fast navigation in the same page, it's create links between a source anchor and a destination anchor.
+
+`type` will determinate if it is an internal page of the site or if it is an anchor link. 
+
+### we need to provide a structure like this
+
+```
+menuLinks: [
+      {
+        name: `file-name`,
+        link: `/link-name`,
+        type: `internal`, //internal or anchor
+      },
+```
+#### Add a Sub-Menu
+
+We can add a sub-menu into the menuLinks, like this exemple:
+
+```
+menuLinks: [
+      {
+        name: `file-name`,
+        link: `/link-name`,
+        type: `internal`, //internal or anchor
+        subMenu: [
+          {
+            name: `sub-file-name`,
+            link: `/sub-link-name`,
+            type: `internal`, //internal or anchor
+          },
+        ],
+      },
+    ],
+```