no a center pin isn't essential and to be honest it would only get in the way to start with,
rig wise, stick float attached top and bottom with rubbers and the shot spaced evenly between the bottom of the float and the hook is a good starting point.
about a number 4 per foot of water,
to start with find a steady flow with the wind coming upstream slightly from behind, then learn to control the float, after this you can move onto more difficult conditions, but don't bother if the wind is pushing into your face, the whole thing will just end up being a pain in the arse.