In order to make a simple backup of the CS PracticeWorks data to an external drive you just need to do a copy and paste of the data folder, or a minimum the .dat type files. You will want to make sure that all users are out of the software before making the backup in order to assure that all data files are copied without issue.
We highly encourage a full backup of the entire data folder every backup, the only exception may be the PWimages folder inside the data folder, which contains files taken within imaging, the chart, and files uploaded to through the attachments feature. The PWimages folder can be done as an incremental backup, only copying the new files since the last backup.
Incremental style backups are discouraged when it comes to the rest of the data folder as restoring from an incremental back up has the high likely hood of corrupting the data due to the nature of the relationship based database structure.