Hey, you’re not an idiot! We only made this game in 4 months so the tutorial is not robust, not your fault at all.
You have to spam the keys quickly in order to break items! Try hitting a bunch of keys at once or using both hands. Some items can be broken while you’re hidden (like the couch and the ball, hide under the couch to break those two!) so use that to test it!
If it STILL isn’t working, try downloading the game instead of playing it on web. Best of luck!! 💕