let's clarify what you're wanting to do...
either:
1. host your own Flash Video on a website you've made in Dreamweaver. Therefore you'll need to embed a flash player on your page, upload the video to your site, link it in to your flash player...
Also you mention ffmpeg -are you wanting to have an upload feature like youtube, or just convert and then upload?
or
2. link it from youtube.
to do (1), you can use
FLV Player - instructions are pretty simple and the examples are good on how to set it up, and embed it in the HTML on your page.
for (2), you just need to upload it to youtube, and when it's up, use the share link to generate the embed code.