HP Prime and directories

[hatchcanyon]

With my former HP 28 I could create directories to get a structure into the variables stored. For example there was a directory named "etec", another one named "wood" and a "tools" directory.

Each one of these directories could have a variable named "len" and all these "len" variables could have different content. Opening directory "etec" showed the right "len" variable for a project dealing with electronics.

My question:
How to create directories on the HP prime?

Thanks for any help!

Rolf