All samples (.wav files) are on DT’s disk (+Drive): only limit is the 1 GB space, and they are available across all your projects.
Samples can be loaded in the 64 MB RAM to be used as is in your project. In each project you will have a different list of loaded samples.
Tip: to load samples, I usually enter SRC menu, choose an empty slot and hit Fn+Yes.
Other tip: order your favorite sounds in a special folder, where you will select all and load samples to RAM when you start a project.
You can also save “Sounds”, i.e. both the sample and all the parameters (Filter, LFO, etc.): 2048 Sounds can be stored on DT’s +Drive library (256 Sounds in each bank A-H).
The Sound pool can be used to store up to 128 Sounds that will be available in your project
Such Sounds are mainly used for Sound locks (Grid mode > hold a trig > turn Level encoder).
All of this is explained in detail in the manual. You will have a better comprehension of the machine if you take time to read it from A to Z.
If you have remarks on this document, hit @eangman on the documentation thread.