Docs: add descriptive alt text for Site Setup figure

Author: Sneha-Goswami123

docs/mastering-plone/add-ons.md

@@ -4,7 +4,8 @@ myst:
     "description": "Extending Plone with features via existing backend add-ons"
     "property=og:description": "Extending Plone with features via existing backend add-ons"
     "property=og:title": "Extending Plone with add-on packages"
-    "keywords": "Plone, Volto, add-on, customizing"
+    "keywords": "Plone, Volto, add-on, customizing" 
+but this is looking very small and I provided you so big isnt't it 
 ---
 
 (add-ons-label)=
@@ -17,3 +18,166 @@ Backend chapter
 For frontend add-ons see chapter {ref}`volto-addon-label`.
 
 The creation of a custom backend add-on is explained in {doc}`voting-story/index`
+```
+
+
+Plone add-ons enrich the CMS by
+
+- adding content types
+- adding behaviors with new fields, relations and other features for existing and custom content types
+- adding blocks to add elementary content snippets to a page
+- designing the layout
+- customizing the editor experience
+- adding content assembling features for overview pages
+
+Plone 6 knows two groups of add-ons: add-ons for Plone and such for the frontend Volto.
+
+Plone backend add-ons provide
+
+- content types
+- behaviors to enrich content types
+
+Plone frontend add-ons provide
+- new blocks
+- variations and enhancements of blocks
+- a theme to design the layout of a site
+- components independent of blocks like a dropdown navigation
+
+Both can be coupled, if a frontend feature depends on a new content type, a new behavior or any other change needed in data structure.
+For example an add-on that has the goal to provide a bookmarking feature depends on a backend add-on that handles the storing of the bookmarks.
+
+Have a look at the curated lists of add-ons:  
+
+
+[Awesome Plone: backend add-ons](https://github.com/collective/awesome-plone/blob/main/README.md)  
+[Awesome Volto: frontend add-ons](https://github.com/collective/awesome-volto/blob/main/README.md)
+
+
+
+(add-ons-find-label)=
+
+## How to find appropriate add-ons
+
+It can be hard to find the right add-on for your requirements.
+Here are some tips.
+
+- Make a list of required features.
+
+- Find candidates on PyPI, npm  or GitHub:
+
+  - curated list of [backend add-ons](https://github.com/collective/awesome-plone/blob/main/README.md)
+  - curated list of [frontend add-ons](https://github.com/collective/awesome-volto#readme)
+  - Python packages on PyPI: <https://pypi.org/search/?c=Framework+%3A%3A+Plone>
+  - Plone add-ons on GitHub: <https://github.com/collective>
+  - Plone core packages on GitHub: <https://github.com/plone>
+  - Google (for example [Plone+Slider](http://www.google.com/?q=Plone+slider))
+  - JavaScript packages on npm: <https://www.npmjs.com/search?q=Volto>
+
+- Once you have a shortlist, test these add-ons.
+  Here are the main issues you need to test before you install an add-on on a production site:
+
+  - Test all required features.
+    Read but do not trust the documentation.
+  - Check if the add-on runs on your required Plone and Python version.
+  - Check if it is currently maintained.
+  - Does it have i18n-support and is the user interface translated to your language?
+  - Does it uninstall cleanly?
+    A tough one.
+    See <https://lucafbb.blogspot.com/2013/05/how-to-make-your-plone-add-on-products.html> for the reason why.
+  - Check for unwanted dependencies.
+
+- Once you found an add-on you like, you can ask the community if you made a good choice or if you missed something:
+
+  - Message Board: <https://community.plone.org>
+  - There is also a talk that discusses in depth how to find the right add-on: <https://www.youtube-nocookie.com/embed/Sc6NkqaSjqw?privacy_mode=1>
+
+- Either extend an existing add-on to fit your needs or create a new add-on that does exactly what you need.
+
+
+(add-ons-installing-label)=
+
+## Installing Plone add-ons
+
+We have two groups of add-ons: backend and frontend.
+
+The training setup starts without any frontend add-on.
+Later on we will add features via a frontend add-on.
+See chapter {doc}`volto_addon` how to install a frontend add-on.
+
+The training setup starts with one backend add-on `ploneconf.site`.
+Let's see how it is installed.
+
+
+### Making a backend add-on package available to Zope
+
+First, we must make the add-on package available to Zope.
+This means that Zope can import the code.
+
+A backend add-on is a Python package.
+Therefore we install it with pip.
+
+Look at the {file}`requirements.txt` file. 
+You add a package to the configuration by adding a new line containing the package name.
+
+If the add-on is not released on [PyPI](https://pypi.org/), we tell Zope where to find the package on `Github` or another repository platform by including the necessary information in {file}`mx.ini`.
+
+```ini
+[training.votable]
+url=git@github.com:collective/training.votable.git
+branch=main
+; tag=volto
+```
+
+Adding the package to `instance.yaml` causes the generation of the Zope configuration to make the package available in a Zope app.
+
+```yaml
+  zcml_package_includes: training.votable, ploneconf.site
+```
+
+Running `make build` has three effects:
+- The build installs the python package with `pip`.
+- The build generates in `instance/` a Zope instance configuration that makes the package available in our Zope app.
+- As soon as the Zope app is started via `make start`, the add-on can be enabled per Plone instance.
+  A Zope app can include multiple Plone instances.
+  So an add-on can be enabled per Plone instance.
+
+```{seealso}
+Documentation {doc}`plone6docs:admin-guide/add-ons`
+```
+
+### Enabling add-ons in your Plone site
+
+An add-on can be enabled per Plone instance.
+
+In your browser, go to `Site Setup` at `http://localhost:3000/controlpanel`, and open the `Add-ons` Panel. You will see a list of available add-ons.
+
+```{figure} _static/site_setup.png
+:alt: Plone Site Setup control panel showing available configuration options
+
+Link to Site Setup
+
+
+Enable `ploneconf.site` now if you haven't done already.
+
+This is what happens: The GenericSetup profile of the product gets loaded. This does things like:
+
+- Registering new content types
+- Registering behaviors
+- Configuring new actions
+- Create catalog indexes
+
+All this is configured in the default GenericSetup profile, which can be found in `backend/sources/<package name>/src/<package name>/profiles/default`.
+In the next chapters we will add here our content type `talk`, configure a catalog index, and some more.
+
+
+
+(add-ons-summary-label)=
+
+## Summary
+
+We have seen in short how to extend a vanilla Plone website with third party add-ons to add new functionality.
+Even if you do not use many of these, they are nonetheless an inspiration on how to implement features in Plone.
+
+
+
+For frontend add-ons see chapter {ref}`volto-addon-label`