The best way to learn how to operate GLS is to spend some time with the Sample Leagues or create experimental leagues of your own, before entering your league data. Run the Scorecards, Enter Results, Update Handicaps, Run League Queries, and practice manipulating the spreadsheet outputs.
Open the GLS database in Edit Mode and Read Only Mode and look at the tables and records. Get a feel for how the database is organized and how the tables work together. Especially at first, do not try to be in a hurry! Double check your inputs before pressing the OK button. Incorrect data input will always be your worst enemy when working with any computer program.
ONCE THE SAMPLE LEAGUES HAVE OUTLIVED THERE USEFULNESS, you can DELETE them using the "Edit Menu" select "Delete League…".