In the status bar at the bottom of the screen he can access his inventory by clicking on the "Inventory" button, on the right side the name of the actual location is displayed, the middle shows captions like when he clicks on "investigate", the character describes the object (and maybe gives hints what can be done with it).

This screen shows the "Inventory" window, that opens on a click on the "Inventory"-Button. The items can be drag-and-dropped inside the window, in order to combine elements (if possible). If the player clicks on an element, it is "loaded" onto the cursor and can be applied on an "active" element in the current location.
