Seems like Goblins covered everything here! Should you have any other questions, don't hesitate to ask. And as far as being new to role playing, I'd suggest starting off small and working your way to something of a grander scale. Large scale plots take many months and even years of plotting. I currently run the largest site wide event- The Connlaothian Civil War, which has been going on since the end of 2012 and in game years, it's going into it's 9th year of war with several 'mini-events' within the larger event. It's a lot to orchestrate, but I currently have the free time to do so (not employed atm) so I was able to focus on that and plotted a lot via Personal Message (PM) and the plotting board to get things going. Also, I've been role playing and running large scale role plays for decades, so I've got the experience under my belt and I'd like to think I have an idea what works and what doesn't :)
I'd suggest presenting your idea on the plotting board and just see where things go. But again, as this is your first game, I'd try to keep the idea to something easy to manage as your first experience and just allow it to grow organically as your story (or stories) progress!
