Need help adapting my temporary music production room, while my grandfather recovers-Acoustics Forum-Acoustic Fields Forum

I was going to submit this on the free room analisys, but it informed there were too many submissions, and as I have almost no money to invest (about 500 -1000 USD), I wouldn’t be able to make too much change. I was wondering if I could have some tips on working on the room

I produce Electronic music and I came to my gandma’s house to take care of her while my granfather is recovering from an infection. I’m adapting this room, that nobody was using, so i can produce, mix and hopefully master in it (although Mixing in it is everything I need to be able to do). I’ve never treated a room before, but I have some “rock wool” I could use (I guess that’s how you call it, I google translated it, “lã de rocha”), and my brother works with wood and 3d printing, maybe there’s something he could help me with (or I could buy some room treatment stuff).

I only have a pair of mackie Cr3. The lower speaker has 3,5 cm diameter. The size of the whole is 20 cm tall, 14 cm wide and long. I will work listening at about 70 – 75dBa.
The room I’m in is 4,0 meters wide, 4,0 meters long and 3,90 – 4,0 meters tall.

The room has Hardwood Floor, brick walls (although I’m not sure), and a plastic like ceiling.

I have a wooden door 2,31 meters tall, 1,0 meter wide, that does a bit of a good job isolating the rest of the house from this room, and there’s a window to the left of the listening spot, 1,30 meters tall, 1,92 wide. There is a bed (2,0 meters long, 1 meter wide, from the floor to the mettress is about 0,55 meters tall, and 1,23 meters tall from the floor to the head of the bed, the tall wooden part behind the pillow, usually in old beds, that I dont know the name of), on the corner of the room, with its side facing the window, and the head suport on the other wall, a wardrobe (1,36 meters tall, 0,75m wide, and 0,42m long) on the door’s side, a wooden chair (0,90 meters tall from the floor to the back suport, 0,46 meters from the floor to the seat, and the seat is 0,46 meters wide and 0,46 meters long) on the bed’s side, a small studying desk (0,78m tall, 0,40m long, and 0,90m wide) beside the wardrobe, and a sewing table (a old wooden type one) (0,73m tall, 0,43 long, 0,90 long) right after the chair, the speakers and their suport (the suport is 1,48m tall), a wooden suport (0,50m long, 0,70 wide, 0,78 tall) for my video monitor and the video monitor (0,57m wide, 0,36m tall), a wooden tall desk(0,81m tall, 1,38m wide, 0,92m long).

The listening spot is configured this way: 1,68m from one speaker to the other, the speakers are 1,16m from the main wall and the side walls, while the listener is 2,61m from the main wall, facing the middle of both speakers. I did all this improvising, I found some sites like amcoustics, noaudiophile, and tryied calculating somethings, but I know there could be much more done, even because I dont know where in the room I need to treat. The position of everything inside the room, including the listening spot can be rearranged, but the room cannot have any size modifications. I placed the listening spot oposing the closet wall, because i thought using the doors of the closet I could, by opening them in some arrangment, help with the acoustics. these doors are 2,10m tall, 0,63m wide, 3,5cm thick, there are six of them, and they open alternating the side from one door to the other. there are more of these, located on top of the bigger ones, they are 0,60m tall and wide, and 3,5cm thick. But what worries me is the window to the left of the listening spot. I thought maybe if i faced the window, if it would be better for treatment, but i didnt have enought time yet.

Pics of the room:

https://ibb.co/zRL7N6q
https://ibb.co/9hpJTfc
https://ibb.co/YT5t5q8

I’ll be working standing, but depending on the best speaker placement, i could work seated.