I took over an existing Magento site which is using 1.9.0.1. I'd like to edit it with a text editor. Eventually I'll upgrade the site to magento 2, but for now I'd just like to be able to edit the css and html files. What is the simplest way to achieve this,?
heh, no such thing as html files.
Magento is a database driven application that uses PHP to extract data from the central database via their own style of MVC architechture and then pump it through dozens of block templates (phtml and other methods) for final assembly to page display. On top of that, they have a CMS system that allows you to create other display pages that also stores its content as database entries.
You'll need to use a FTP client to edit the CSS from inside the admin panel.
If you want to create a new theme you start with creating a new folder in Magento>app>design>frontend and copy the files you want to change in your theme. So if your theme will change the 1column layout to start with, you'll end up with this:
Magento>app>design>frontend>[YOUR FOLDER]>default>template>page>1column.phtml
Same goes for the Skin folder. When you want to change the main css file for your theme you'll end up with this structure:
Magento>skin>frontend>[YOUR FOLDER]>default>css>styles.css
Makes sense. Actually the main thing that's confusing me is pretty basic.
1. Do I need to use and amp server package to a achieve this, or is it possible with something like filezilla?
2. How do I download the file structure from an existing website from the admin panel?
Actually changing files directly using FTP or even SSH is an accident waiting to happen. Please do yourself a favor and use versioning software (such as Git) to deploy files to your live environment. At least consider it.