Best place I can recommend is the Getting Started which walks through the basic storage setup. You can create the datasets in your preferred media folder naming scheme. Then move on to Sharing, Backups following the next guide and so on.
A dataset is a file system. It can, and probably should, contain multiple folders. Shares are based on datasets, not on folders.
All your clients can use SMB shares.
Do the different clients want to access the same data? One dataset, and one group with multiple users. Folders as you like.
Do the different clients want different data? Should some data be served only to certain clients but not to others? Different datasets.