You don't need to be a master programmer to do something simple, like automatically fill in a field. You just need to know how to get started.

In this example, the Date_Entered element in the sample Customers application is automatically filled in with today's date.

1. Open your Form in Designer.

2. Choose Program Layout from the Commands Control Panel. The Program Editor opens.

3. From the Element dropdown, choose the Element you want to program. From the Event dropdown, choose the event that will trigger the program. In this case, we are programming the On Element Entry event of Date_Entered. This will run when you enter the Date_Entered element.

4. In the Program box, type your program.

5. Test your program by selecting Test program from the Test menu. If errors appear, check your program and correct them.
Note: Double-clicking on an error takes you right to that line of code.

6. If no errors appear, close the Program Editor by choosing Close Program Editor from the File menu.

That's all it takes to create a program. Don't forget to Save your layout! You can try all your programming, except X commands (like XLookup) in Preview mode.

More Information:
Sesame Programming Guide