Out of the box dwm is light, fast and simple. If you want extra functionality - and most users do - you'll edit the source code, recompile and reinstall it.
Defining tags and workspaces
Users often confuse dwm's tagging system with workspaces (or virtual desktops). Once you understand that tags are not workspaces, you'll realise why dwm was given its name - dynamic window manager - and how powerful it is.