You can make backups manually by copying files from your working computer to another means of storage, for example an external hard disk. This process may, if you like, be computerised by means of (paid) software. Daily backups are made by ICT Services of any files saved on the UvA network disk.
How often you make a backup depends on how often your files change. Making a backup can be very time-consuming, depending on the number and size of your files. You might consider making an integral backup of all files to start with, then each week only those files that have changed, and copying all files to your backup medium once a month.
If you store both the original files and the backups physically at the same location, there is a chance that the files may be lost, owing to theft or fire. You minimise this risk by storing backups at two or three different locations.
Any digital file can get damaged in the course of time, for example as a result of the medium on which it is stored becoming obsolete. Therefore it is important to test periodically if the files are still complete and usable.