Hi, thanks for giving my game a try.
What do you mean by intro? After discarding the clue “Click on this clue”, there should appear a new action “Answer the door” in the action area (at the bottom of the screen). You should drag it into the clue area. Then you can click on it to reveal further actions. Clicking on any clue reveals actions that you can take. The actions are different for every clue.
Be aware that you can ‘softlock’ yourself by discarding all your available actions (dragging them from the action area directly into the discard areas). You can quit to menu and press play to reset the game.