Hey Emwilson, congrats on making the move to Joomla!
Firstly, you can upload a Joomla installation into a subfolder of your main website root using an FTP program like Filezilla. Once you've gone through your installation and everything is working well, you can access your website in that subfolder. So, for example, if your normal website had an address of
www.website.com, and you created a folder using FTP called "newsite", you would access your Joomla installation at
www.website.com/newsite (and access the administrator side of things at
www.website.com/newsite/administrator).
Once you have gotten your Joomla site up to speed and ready to go, you would first backup your old site (and its database), download your entire "newsite" folder to your computer, clear out the old site content from your website root, and then upload the contents of the "newsite" folder back onto your root.
You could also keep your old site available by creating a subfolder called "oldsite" (or anything else that you wanted), and upload all of your old website files into this folder. You could then access your old site at
www.website.com/oldsite.
Joomla is already equipped to display a blog. You simply need to create a blog category, create a menu item that links to this category with a blog display format, and save any new blog articles to this category.
You can add commenting ability to this with several different extensions. This one is a favorite:
http://extensions.joomla.org/extensions ... ents/12078... but you can find lots of others by search for comments at
http://extensions.joomla.org
_________________
Ryan
Numinous Productions
Custom Joomla Templates, Joomla Troubleshooting and Personalized Tutorials
http://www.numinousmedia.com