Gradebook can seem daunting at first, so here are some handy things to keep in mind.

• Have a lot of assignments?  You should probably set up the Categories first, and then you can choose what Category you want your assignments to be part of when you actually create the assignment on the main page.
  
• Don't worry about Scales: Moodle only allows for custom scales based on text, not numbers.  If you want to set up a scale of Satisfactory through Unsatisfactory, then Scales will be useful.
  
• The Course Settings section of Grades, though the name of the section is the same, is not in fact the same as the overall Course Settings that you can get to directly from your course Admin Block.  You can turn viewing of grades on and off for students from the main Course Settings page.  You can do much more tweaking of Gradebook's settings from within the Gradebook Course Settings.
• If you used Gradebook before summer of 2008, you had to do things in a specific order.  The current version of Gradebook is much more lenient, and you can add or change things as you prefer.
• Students can't see their grades? Gradebook is designed to be used either for your reference only, or so that students can see their grades.  By default, your automatically created course pages will be set so that students can't see their grades.  To change the setting, go to the Settings link under the Admin Block, and within the section called General, look for "Show Grades."  Change it from No to Yes, and your students should see their grades.