Doors and Rooms 2 Walkthrough: Chapter 1 Stage 3

First of all, there is a cabinet right under the clock. Open the cabinet doors and you will find a battery pack inside.

There is a working flashlight under the table.

Lastly, there is a screwdriver on top of the DVD player, under the TV.

Item locations

Go to your inventory and dismantle the battery pack and then dismantle the flashlight as well. You will get a total of 3 batteries.
Now tap on the door lock and use the screwdriver on all four screws. Tap again to remove the cover, enter the 3 batteries into the slots one-by-one. The light will turn green, now push on the open button and the door is unlocked.

Bonus Star and Quiz

The bonus star is on top of some blue flowers located on the lower shelf on the left wall.

The bonus quiz requires you to enter the time that is displayed by the clock on the wall. The clock doesn't move and always shows 12:35 as the time. So tap on the TV hanging on the right wall and enter 1235 as the code.