Make a post, with in it your submission (video, song, drawing, painting, sculpture, whatever you want to submit.)
In the tags, put #creativecomp as the first tag, followed by what you want, and then copy and paste the link of your post into your comment.

I hope that helps!

Seth, a fellow submitter ^__^

Edit: Oh, and follow @Sammosk and resteem his competition post. ^^