This depends on the type of filling system of your pen. There
are many types of filling systems: lever-filler/bladder, piston-filler,
plunger-filler, converter, to name a few, and the filling
procedures will vary. Jim Gaston's web site has very good
information about the procedures for most fountain pens.
Please visit his site at: http://www.jimgaston.com/filling_vintage_fountain_pens1.htm
for more information.