diff --git a/docs/customising.md b/docs/customising.md
new file mode 100644
index 0000000..57aff9b
--- /dev/null
+++ b/docs/customising.md
@@ -0,0 +1,70 @@
+# Customizing
+
+## Megamenu links
+
+The [Megamenu][megamenu-internal] has two parts:
+
+- [Internal / system][megamenu-internal]
+- [External / configurable][megamenu-external]
+
+[megamenu-internal]: https://dd.digitalitzacio-democratica.xnet-x.net/manual-usuari/menu-principal-dd/
+[megamenu-external]: https://dd.digitalitzacio-democratica.xnet-x.net/manual-usuari/eines-externes-megamenu/
+
+Only [External links in Megamenu][megamenu-external] can be modified using the interface, [internal links][megamenu-internal] such as `https://admin.DOMAIN` cannot be modified using the interface.
+
+In both cases a customization and provisioning can be made editing files `custom/menu/custom.yaml` and
+`custom/menu/system.yaml`.
+
+The examples of these files are in `custom.sample/menu/custom.yaml` and `custom.sample/menu/system.yaml`.
+
+### `custom/menu/system.yaml`
+
+When editing `custom/menu/system.yaml`, keep in mind that depending on the `href` value and if is defined the `subdomain`, each link will be generated different.
+
+Also note that relative urls must start with `/` or `#`.
+
+```yaml
+# Example of apps_internal in custom/menu/system.yaml
+apps_internal:
+# Generates the link https://DOMAIN/about
+- href: /about
+  icon: fa fa-rss
+  name: About
+  shortname: a
+# Generates the link https://moodle.DOMAIN/courses
+- subdomain: moodle
+  href: /courses
+  icon: fa fa-graduation-cap
+  name: Courses
+  shortname: courses
+# Generates the link https://external-url.com
+# because url is absolute
+- href: https://external-url.com
+  icon: fa fa-book
+  name: external-url.com
+  shortname: external url
+
+```
+
+## Peu de pàgina en el login
+
+The footer is part of the Keycloak login theme, to modify it, it needs to use a theme based on 'dd' theme.
+
+To make things easier, in directory `dd-sso/docker/keycloak/themes` there are these subdirectories:
+
+- `dd-custom`: an empty directory, what is created here, keycloak will use as a new `dd-custom` theme.
+- `dd-custom.sample`: an example of how the theme `dd-custom` would be prepared in order to replace the footer.
+
+So, to customize the footer, you need to copy the contents of `dd-custom.sample` to `dd-custom`, then edit `dd-custom/login/dd-footer.ftl` to suit our needs.
+
+Once this is done, in the keycloak administration interface you need to pick `dd-custom` as a login theme:
+
+`https://sso.DOMAIN/auth/admin/master/console/#/realms/master/theme-settings`
+
+> **Note:** dd-custom directory never will be updated, so it is your responsibility
+> to review the chnges with maintained `dd` theme, the contents of directory `dd-custom`
+> and contents of `dd-custom.sample` to make your customization compatible.
+
+## Integració amb altres eines
+
+It is possible to integrate DD with other tools, read about it in [integrations](integrations.md) section.
\ No newline at end of file