Preparing your knowledge of what affects SMS operation, what cases you need to take in to consideration.
Can you briefly summarise the cover of your network you plan to deploy to, maybe we can point you in the right direction....the size and coverage/complexity will gauge how much you really need to prepare and know before rolling out.
In regard to the capacity planner, I have never used it, so I couldn't even guess.
Hope this Helps.
Neil J Cotton
njc Information Systems
Systems Consultant