Hi,
Maybe I am getting confused, but I would say you need to use the "content management" funcion, which allows to type text or html code and then add it to your front page (thanks to the front page layout) or to create new pages (everything you type will be included to a new page with the general header and footer of your site).
You have to type a short name (the name of the page you will access here : yoursite.com/static/specificsection/shortname.do).
Here is a new links page I've created myself (empty) but as you can check, I can include new a content inside a new page with my chosen name :
http://sexonline4free.com/static/partner_content/gotlinks.doTo include text to your homepage, you have to add it thanks to the "front page layout" funcion (if you have a co-branded site) or use the banner section in the "content management" part. You will be able to add any content added to the banner section to your home page, from the "front page layout".
Regarding your question about addind code to all pages, this is not possible I guess. You can edit your main page, and add new page. But adding code to other pages or adding banners, adsense code or whatever at the bottom of the existing pages is not possible.
Also, your right Chris, the file management is for pics only : quote from my admin after trying to upload a .zip file :
Sorry, but the image format is invalid. Only .jpg, .gif or .png files of not more than 2Mb in size can be used
Hope this helps, I'm a newbie to WDP but it worked for me. Just tell me if I'm wrong !
Thomas