First you need to upload video file to YouTube.
In order to upload video content to YouTube, you will have to sign in with either a YouTube or Google account. There is an “upload” button at the top right of the YouTube homepage (you can sign in from there too, or create an account). If you sign in with a Google account, you will then be instructed to created a YouTube account (or link your existing YouTube account – if you already have one – to your Google account). Once signed in, you can upload video by clicking “upload” and searching for files on you computer.
[Getting the YouTube Video onto the Blog]
Once your video is uploaded to YouTube, you can simply copy the content listed in the “embed” tab (not the “URL” tab) that is listed to the right of the screen (when you have the video open in YouTube). Paste the “embed” content into the post just like any other “Link.” When writing a post on the blog, switch to “HTML view” (the default is “visual”) and paste the embed content there. The “HTML” button is to the right of the editing buttons. As soon as the content is pasted, switch back to “visual” mode and continue the post (nothing else should be done in HTML mode unless you are comfortable with editing HTML). The video will then play directly in the post and will hardly take up any server space on the blog.