The Klingon grammar is really not difficult. Beginners may ask a new question at the page of beginners' questions. Advanced speakers my find some interesting grammar questions. If you are not familiar with all that linguistics stuff, read the article about grammatical terms first.
It should be remembered that even though the rules say "always" and "never," when Klingon is actually spoken these rules are sometimes broken. (1)
The best way to make an overview of the Klingon Grammar is using the chapters of Marc Okrand's Klingon Dictionary. This also makes it easier to look up in the book.