After images, videos can be a tricky subject for new WordPress users. I think the easiest way to handle videos in your posts is to use YouTube and their embedded code. To add a video, first upload your video to YouTube. Then…
1. If you bring up your video on YouTube, there is a button labeled “embed” just underneath the video. Click on the button.
2. Clicking the embed button will open up a box with html code and a number of options the most important of which is the size of your video. In the light blue box, enter the width of your post area in WordPress. Usually it’s about 500 px. If you don’t know, you can always come back and do it again, so don’t worry about guessing.
3. When you enter a special size, it automatically changes the html code in the box above. If you’re leaving it at the default 560px, no changes are made. Highlight all of the code and right click -> copy.
4. In WordPress, on the “Add New Post” page, make sure the post body block is set to “HTML” and paste your code into the post area. Be careful to not toggle back to “Visual” until you have saved your changes. For some strange reason, the code will disappear. Also, the video may end up at the top of your post. If you feel comfortable with the HTML, just move it around to the appropriate location and save it. If you don’t feel comfortable, you can cut and paste in Visual mode after you’ve initially saved it.
Hope this helps!