Hi,
Really a bit more info and maybe a screenshot would help. Like what are rooms?
But as a guess I would say rooms are also often known as levels (that is the direct translation in a few languages ive noticed)? So:
If you have a player object that you want to move to a new location in the same scene, you simply use 'set position' (as a way of changing rooms/levels without loading a scene) .
So create your two levels in the same scene, then make sure they are not visible from each other. Then when yoyr player completes a level, do the gui stuff that you do and 'set position' of the player to the 2nd level.
This is based on me guessing a lot, as I said I dont really understand the issue fully, so it may not help but good luck with it and try to provide a little bit morw info (also screenshots help break down language barriers
) if it does not help.
PS: Ive just noticed you mention that you "have no idea how to code". Do you have the playmaker asset? If you do then you do not need to code any gameplay element.