Here is a simple beginner tutorial of how to read schematics...
http://www.instructables.com/id/HOW-TO-READ-CIRCUIT-DIAGRAMS/
The major difference between Solid State pinball schematics and Electromechanic pinball schematics are the symbols involved.
The SS pins use electronics symbols, the EM pinballs will use more electrical symbols since there technically are no electronics involved in EMs.