1. Install Joomla in the route of your website (lets say the base URL will be www.site.fr, physical location depends on your server, lets say <root>)
2. Install Magento in a subdirectory of your website (<root>/store) The URL becomes the www.site.fr/store
3. Go to http://www.jfusion.org/index.php/docs/doku.php?id=visual_integration;guide With Magento we are going to use the direct link method. Joomla can be run in a wrapper and you can experiment with it, but we are going to get it to work first using the easiest and probably the better method to setup for the JFusion v.1.2.x
4. Go to Joomla admin and install JFusion from www.jfusion.org, follow the documentation step 1, 2 and 3 from the documentation at http://www.jfusion.org/index.php/docs)
5. Go to Magento's admin and create an api user and api key. See http://www.jfusion.org/index.php/docs under Magento for a “how to …”. ( you create an API User and Key. If you complete this step successfully JFusion will stopp to complain about a api/key problem. Ignore the complain about Magento needs to have userregistration disabled because it's a slave. This will stop once we made it a master.)
6. While we are in Magento's admin Check System/configuration/general/web/session cookie management. Cookie domain and path should be empty, HTTPonly should be set to NO. Also check: System/configuration/general/web/Session validation Settings. All should be set to NO
7. Now configure the plugin. Read the paragraph in the doc and follow it, but also use this documentation to setup the Magento plugin (the link is at the bottom of the webpage about configuring plugins )
8. Note: Setting up the cookie domain and path is the tricky stuff so follow the guidleines please
9. USE SIMPLE USERGROUP SYNC! We can go into the advanced mode later. Keeps things simple to get it working.
10. DO NOT PERFORM THE USERSYNC!
11. At the end we are going to have Magento as Master and Joomla as slave, BUT FIRST SET JOOMLA AS MASTER AND MAGENTO AS SLAVE! We need this to make user we have a user in Magento that is linked to Joomla's admin. This user will be created automatically when you follow the instructiosn. If you don't, once made Magento master you will be locked out yourself from Joomla (this part is deprecated since the version of Jfusion v.1.2.x).
12. OK, so far so good. Now do the final checks. First the loginchecker. Use your Joomla admin credentials for the first Login Checker test. This will create the a customer account in counterpart in Magento. If the Loginchecker shows all is OK, create another tab in your browser and open the Magento homepage. You should be logged in.
13. Test the logout routine in the same way.
14. If all is correct, Enable the Jfusion plugins (follow the doc), go to Joomla's frontend and login using a valid Joomla user. Test if you are logged in. OK? Test logout.
15. OK? Check in Magento/admin if you have a user with an email address that is the same as your Joomla admin.
16. Correct? Make Joomla slave and Magento Master. and repeat step 12.
17. All OK? Congratulations you have successfully setup Jfusion with a magento integration.

If you meet problem, check first the path and the domain of the cookies in each application (thanks to your browser) then to each configuration (magento plugin of jfusion and magento self). Probably you will need to set a '.' in front of the domain in the cookie domain configuration (e.g. .jfusion.org), mainly for the subdomains cause of Firefox implementation.