Thank you for your interest in Acronis software
First of all, Acronis Nonstop Backup will create an initial full backup of the partition you've selected for protection. After that it will create incremental backups every 5 minutes and you will be able to restore your documents to the exact state of time. Older backups will be consolidated automatically, so by the end of the day you'll get a single archive.
More detailed information is available at the Chapter 7 of the User's Guide
I may also recommend you to download the trial version of Acronis True Image Home 2010
in order to check how it works on your computer.
Within Windows the trial version if fully functional for 15 days.