am quite new to Episerver Cms, trying to build a site and want to ask this query
me basically a Flash/ Flex pro, thinking can i able to able to buit a fully based flash in Episerver CMS
And the Site has basic navigation and stuff. so not much complication involved apart from loading dynamic content from the xml
Two things you need to do. Add page types for the editor to use, and generate the XML markup for your flash application. I've written a guide to creating an EPiServer site from scratch that should help you get started with EPiServer. When it comes to generating the XML markup there are plenty of tutorials and guides that'll help you with that (after you've learned how to retrieve the data from EPiServer).
Hope this helps.