Does it works well with magneto 1.9 which is the latest edition or should i fall back to 1.8

I installed 1.9 and seems to work.
Can someone direct me to install extension, you direction states
1. Copy all the folders of each extension folder in mage_ext to the root of your Magento site folder on the server.
2. Login to your Admin Panel on the stage localhost: http://localhost/magento/index.php/admin/.
3. Navigate to System >> Configuration.
4. To enable an actual extension, in the JoomlArt section, enter this one’s tab and set Enable to “Yes”.
Where is Joomlart Section?
I should add extracted files under mage_ext? and create sub-folder for each extension?
I seem to be stuck hereThanks.