Here's a quick visual walkthrough showing how to set up a new Simple Backup Job
Note: the images in this screenshot show Jungle Disk (Formerly Workgroup), but the steps involved apply to Desktop Edition as well
Step 1: Click "Configure"
Step 2: Select "Simple Backup" and create a new job
Step 4: Select "Schedule" and adjust (if necessary)
Step 5: Select 'What to Backup' and then click "Add or Change Backup Folders"
Step 6: Choose which folders to back up from your computer
Note: For more information on the available modes/configurations for backup, check out Understanding Modes in 'What to Backup'
Step 7: Verify your backup configuration
Step 8: Adjust your "Backup Options" (if necessary)
Step 9: Click Start Backup now if it's a good time to start
Note: This could take a while! Alternatively, you could wait for the schedule to start the backup automatically.