You might think of creating your own phrases. I'd suggest waiting until you are finished with your lessons before you think of creating phrases. The intermediate board has a discussion on phrases and creating your own, so you can work on that later. For now, learn the phrases given.
Remember, if you come across a word and it seems odd, it might be a phrase. Also if you think something is a phrase, it might just be a word. Use context to help you with this.