You can use the code below to post it to the post, and edit the width and height:<iframe width="560" height="315" src="https://www.youtube.com/embed/SHTItkyNaTI" frameborder="0" allowfullscreen></iframe>
I can do this for you remotely if you like.
By connecting to your PC where the blog is open, and doing it from there.
You can edit the post instead of pasting the link paste the code above, and edit height/width with the number you'd like.
Let me know how it goes.