stephan75
(stephan75)
2
Maybe an entry point can be this?
http://wiki.openstreetmap.org/wiki/Import
It is also important to know before “importing” whether some objects on your map are already present in the original OSM data.
It is no good when some data set is imported as a bulk and some objects are doubled then.
So the best way should be to work with layers: one for your map and anothe for the OSM data so far. Then, add all missing objects to the OSM data step by step.
Another question that has to be answered:
What is the origin of your map?
are you really allowed to use it for OSM purposes without breaking any other licence or copyright?