It's time to break the wall between the 2 rooms
Let's see the different layers used at the time ...
...deeper ...
...more deeper ...
Of course, in the first room (v1), there is an electricity wire that come all along the wall (you can see a part of it on the last picture). The hard job will be to deviate that wire because :
1) This will be an entry to the new room... I don't want to have any electricity wire in my foot of course
2) The electricity must be still available behind all the wall in the first room of course
3) I need to bring electricity for the new walls, the one you can see in the new room. For the other wall, I'm taking electricity from another source.