As far as my street cred goes...
I did mountains twice when I went in 2010.
Dude don't stress about Ranger school yet. You've got plenty of time to start worrying about that. If you are really worried about it, pick up a ranger handbook and start looking through it. All the answers are in the Ranger handbook, they don't just make shit up every class. There is a standard and they hold stud to it.
Also, there's another little book called "so this is ranger school." Written by a student who kept a journal. Pretty good day by day of what to expect.
But...like I said earlier. Don't stress it yet. It will come soon enough and you'll have wished you ate all your favorite foods and got drunk more haha.
IBOLC will help you prepare physically.
the mental part (THE MOST IMPORTANT PART) is all up to you.
EDIT- As far as your original question you get a typed hardcopy version of the order. If you are in charge of the patrol you immediately break up your squad into different groups to tackle the OPORD. So some guys will break off and go build the terrain model, other guys will knock out terrain analysis and light/weather data, other guys will knock out ENY SITEMP...etc. As the leader of the patrol, you need to focus on paragraph 3 (Execution). Pretty much you need to talk the fight and how you plan to execute actions at the objective. So if you are doing a raid you need to talk the establishment of security, support by fire, and where your assault element is going to go. THen you need to talk about direct fire control measures, ie when/how you plant to shift fire as you assault through the objective. Once everyone is done w/ there little piece of the pie, they will usually give you what they came up with on notecards. Then you put all the notecards in order and about that time the RI comes walking back to hear your brief. You are on a serious time crunch, so there is no way you can tackle the OPORD all by yourself. When you are in charge, let others help you. When you are not in a leadership role, don't be that buddy fu*ker who shams and keeps falling asleep while everyone is trying to help out on the order. That's where peers come in...
Everyone I've ever met who failed Ranger school had an excuse. I have no sympathy for quitters as I sat in mountains recycling while my unit was deployed. How do you think I felt?
If you are going to be an officer, don't show up to my unit as an infantry LT without his tab, period.
I firmly believe Ranger school is the best small unit leadership school the military has to offer.