advice for my basement studio

here is my basement with all dimension , the comments are above the pics Mostly I'm going to do some mixing, mastering, listening. I don't listen music very loud, but it is mostly electronic stuff. Now first thing i'm going to do is to isolate room , to prevent sound leaking The back wall is going to be isolated with Ursa mineralwool and plasterboard, but there is the problem with the window you can see on the picture. And celling is another frontier of my neighbour ( it can be seen in all off pictures)the celling has wooden beams (470x23x20 cm) and in the middle wil put mineralwood ticknes 20cm and plasterboard 0,125mm, on the metal grid so the celling will set down about 3cm. also I would like to put sliding door. so if you have any advice you will be more then welcome thanks