In order to keep things simple, I would like to invite all players to make ordinary people for the start. Commerce with the sunlit world, the surface, the sane and 'normal' world we are all familiar with, continues throughout the convoluted history of Fallen London, so people from normal walks of life can and do end up in the Neath, sometimes even in groups. Time is another thing that is odd in the Neath (which is where we will be starting), so it is entirely possible to have someone born in the late 1800's looking like a teenager and rubbing elbows with an elderly gent from sometime in the late 1990's.
However, if anyone is familiar with the setting, you are welcome to make something appropriate. I do try to be as flexible as reasonable, but I will hold such ambitious souls to a higher standard.
So! No experience necessary! Come, sign on to sail the Underzee! The vessel is yet to be named, but the docks groan with anticipation of your step.