I would like to be prepared in case something goes wrong, where can I get a form to request a review of my case?
You can download VA Form 20 - 0996 : Higher - Level Review PDF
I have a follow-up question about claim's status? What happens when I request a clarification of my decision?
You do not need to do anything while you wait, unless the VA sends you a letter asking for more information.  If the VA does schedule exams for you, be sure not to miss them.