Hey Neeka!
I just checked your "Test" game, with the forest rooms.
To link two rooms, you need a model (I added a Door model for example), then select the room (need to be displayed on the canvas), and drag the model to it.
From here on, select the instance that was just created (we call this an "item"), and go to the Options.
You can add various options here, but for your case add a "Go to room" action. In the Value field you need to put the destination room's ID.
I just made this little demo for you right in your game :)
If you have any further questions, please let me know!
(If you can't reproduce it, I can make a little video too.)