PHP Plugin Needed for Embedding Videos

Can anyone tell me if a total novice can create a WordPress PHP Plugin for embedding HD Videos into my WordPress Blog from another website?

If so, do you have a link or article that can illustrate a simple step by step approach to creating a custom PHP Plugin for this application for my WordPress site?

I am such a novice that I am unsure of even which version of WordPress I am using, or how to find out… however I do have a little bit of information I read before which essentially advised against updating versions of WordPress which could totally destroy one’s Blog.