Building small home studio on attic

Hi All, Im would like to build (or actually let buils) a studio room at the attic of my house. I have no experience at all but I have been reading a lot of posts on this forum, homerecording.com and several other forums. Unfortunately its very hard to find a contractor who has any knowledge of building sound isolated rooms, they will build it if I can give detailed instructions of how it should be done. As I understand the entire "soundproof" concept can be messed up when mistakes are made in the construction so I hope you guys can give me some advise. English is not my native language but I will do my best to make it all clear. Current situation: My small home studio is located at the attic of my house. I live at a corner so only have neighbours at one side. Unfortunatly because of the stairs the room has to be build at the neighbours side of the house. In my attic I have a concrete floor and walls, the sloping roof is made of this wooden plates. The side of the attic where the room should be build has on both sides of the sloping roof a windows, 1 roof windows and 1 dormer (hope you guys know what I mean, translated ther specific window names on google) The size of the room is about 4 meters (at the the floor, both sides have sloping roof) x 3 meters long. What I would like I produce house/dance music so there are some nasty low frequencies involved. Maybe its usefull to mention I use ADAM A7X monitors with no additional sub. I would like to be able to put up the volume at a reasonable "working" lever, it doenst have to be extremly loud but I just want to be able to hear how it sounds at good level. At the moment when I use the speakers at very low level the kick can even be noticed 2 floors down of my house. Im very confused. I can imagine my situation/need are different then someone who wants to build a drum room. Im not sure what materials to use and what construction would provide enough sound isolation for what I want. Also Im very unsure of the construction. As i unserstand there is no room for mistakes and as materials and labor costs a lot of money I want to come up with a good design. Can you guys give me someood advise? If you like I can provise some pictures of the attic to make it more clear. Thanks in advance, Alex

"If you like I can provise some pictures of the attic to make it more clear." That would be helpful as attempting to construct an isolated environment in an elevate space is always tricky...

Thanks for your reply. Here are some pictures, sized them down a bit for upload. Hope i can get some advise. Thanks in advance Alex

you might be better off facing the big window and taking advantage of the sloping ceiling. then covering the beams with absorption. the space may be too small to add any significant isolation = perhaps doing some isolation testing to see how much isolation you need is in order...