get yourself a good muzzleloader building book - such as Peter Alexanders
http://grenvillegunsmith.blogspot.com/
the process is the same since a flintlock is a side lock- Peter is in the process of putting out a dvd set off instructions.
one og my builds I can post later, but as Chris says - start with the plate and build up as you go, check the squareness of the plate to the bottom often.