Apart from the answer that @happyme gave, you need to upload the video to YouTube, and then copy the URL and embeds in your post. However, if you are using viewly then you just upload in Viewly and it automatically becomes a Post. So your job is reduced.
Makes sense ? If not, then please raise questions. I don't think, any question could be stupid :) Its curiosity instead.
I uploaded several videos on Viewly and all went well.