When you click on items printed in green underscored with a solid line the window's contents will change to an explanation of that topic. If you are feeling a bit lost and haven't tried the very useful Windows Tutorial please do. Once you have finished this work your way through the Windows part of the Tutorial. Ask for help if you need it. It cannot be stressed enough how important it is to take backups of your work.
Disks can and do fail, often at the most awkward and inconvenient times.
A safe and sensible backup regime is given in Contents Directory and File Operations Directories and Files Directories can be thought of as document containers with their contents being files. The top level directory is known as the root directory. Normal working files can be kept in the root directory but it is sensible to have different directories for different types of file. For example someone working on two different projects should maintain two directories. Here is the directory layout of a disk.