Embedding Vimeo on website

I created my website using Serif Webplus XL, and want to embed my videos on Vimeo to my site. I know nothing of HTML (I know, not a good start). I can create an HTML page in Webplus, copy and paste the code from Vimeo and the videos appear on my site and play back perfectly. Thats all fine, but when I embed another one or two they appear below each other but staggered all over the page. Can anybody tell me how to line them up??
Thanks.