SAP functionality can be called/started via transaction codes and reports. The main transaction codes also live in SAP's menu,s but when you want a short-cut to certain functionality, use the transaction code. They are listed in table TSTC which can be viewed with transaction code SE16 (or SE16N or similar).
Note that TSTC output lists the description, which is in fact on TSTCT. If you want to search for a transaction code using a description - use SE16 on TSTCT. As for the meny: if you are in need to know where a certain item is in SAP's menu's, there is an easy way to check. Use transaction SEARCH_SAP_MENU.
Which will list something like:
Node Transaction code Text Nodes SE51 Screen Painter Preceding node User Interface Preceding node Development Preceding node ABAP Workbench Preceding node Tools
Note that wildcard search in SEARCH_SAP_MENU using * is not supported.