New symbols can be created using the MWOffice.Project.Symbols collection methods. Like most collections in theAPI you'll use a method on the collection to add a new element into the collection. In the case of symbols this requires a three step procedure:
Create a SymbolRecord object using the Symbols.CreateSymbolRecord method.
Add your shapes and nodes to the SymbolRecord object.
Create the symbol using the Symbols.CreateSymbol method specifying a name and providing the SymbolRecord object.
So the basic procedure is get a SymbolRecord, specify the symbols details and then use the symbol record to create the symbol. Let's take a look at what this looks like in code,