How to treat my room?

http://ibb.co/pZRxpyX Hey guys, I‘d need some advice on room acoustics and room treatment. I wanna turn my „music room“ into a home studio. I‘ve already made several recordings in this room but I wanna make it more pleasing to the eyes and, more important, enhance the room acoustics. I record vocals, guitars, drums, etc. The enclosed picture (link) shows my room plus the measurements of it. Just ignore the green and red lines in the picture. (I live in Europe so the length units given are in Centimeters.) Mixing as wells as recording the artists takes place in the same room. The walls are made of concrete and the ceiling is made out of a material called Ytong. Oh and the room has a vinyl floor in it. So, I would like to ask you guys some questions: 1) where would be the best place to set up my monitors? Logically, I’d record the artists on the opposite side of the room. 2) How should I treat the room? I know that one should install absorbers on the first reflection points.. but yeah thats pretty much all I know. How should I treat the wall facing my monitors? Regrettably, I don’t have the money to let a room acoustics guy measure out my room. The ceiling is only 7" tall, which makes treating the ceiling most likely impossible because I would run out of head space. I know it’s not the best room for my project but I don’t have an other option. I’m looking forward to your answers and hopefully you guys can help me out. Thanks in advance, Chris.