Most functionality is available using a mouse, eg. activating a window at the edge of the monitor by clicking on it. In wayland its possible to navigate with 3-finger swipes on the trackpad. But the primary focus is making an environment which works well with a keyboard.
All keybindings start with the Super modifier. On most keyboards it's the Windows key, on mac keyboards it's the Command key. It's possible and recommended to modify the keyboard layout so that Super is switched with Alt making all the keybindings easier to reach. This can be done through Gnome Tweaks under Keybard & Mouse ? Additional Layout Options ? Alt/Win key behavior ? Left Alt is swapped with Left Win.... More Info »
Most keybindings will grab the keyboard while Super is held down, only switching focus when Super is released. Escape will abort the navigation taking you back to the previously active window.
Adding Ctrl to a keybinding will take the current window with you when navigating.
Swiping the trackpad vertically with three fingers lets you navigate the workspace stack (only available in Wayland).
There's a single scrollable tiling per workspace. Adding another monitor simply makes it possible to have another workspace visible. The workspace stack is shared among all the monitors, windows being resized vertically as necessary when workspace is displayed on another monitor.
PaperWM currently works best using static workspaces, this can be turned on with Gnome Tweaks under Workspaces.