The hotkey feature is very straightforward. To assign an item to a hotkey, simply hover the cursor over the desired item and press one of the numerical keys from 0-9. You can now skip opening your pack and switch between weapons and items simply by pressing the hotkey.
The update also includes some added hints, an improved cutscene skip prompt, and more functionality for the ‘Back’ button. Here are the full details of the announcement:
- Added hotkey system for keyboard/mouse. Assign hotkeys in inventory by pressing numerical keys 0 through 9 on hovered items in inventory
- Added hint for hotkeys to loading screen
- Improved cutscene skip prompt; will now appear briefly at start or show when common skip keys are pressed (esc, space, etc)
- Added heavy attack tutorial to loading hints
- ‘Back’ (default Esc) will close Tutorial book, Construction book and Grab bag interactions
Source: Steam Announcement