5.1 Control room design

Hey guys Im in the planning stage of setting up a 5.1 surround mixing control room in a existing carpeted room under my house. I would defiantly like to fully fit out the room at a later stage but i have some projects that need to be finished asap and dont have the money just yet to do a full fit out. John if you get to read this can you please contact me in regards to costs for plans to complete the room at another stage in the future. My first 5.1 surround film is coming up in two weeks so i would like to treat the room especially working on the bass response. I mix the occasional live gig in dongers at festivals so i would like some the panels and bass traps to be relocatable to be used in other locations if possible. The only treatment i have at the moment is 3 x 900 mm x 1800 mm 100 mm Panels. Made 2 x 50 mm Bradford ultratel rigid fiberglass and plywood. Can we work them into the equation. If any work i do now could be incorporated in a more comprehensive fit out at a later stage in this room that would be a bonus. Some help in how to approach this would be fantastic. Do i need to analyze the room before i start with any treatment ?( whats the best way to do that? I can get access to a reference mic) I have been getting away so far with out any complaints form the neighbors though if more work came in i would need to look at sound proofing the room at a later stage. Some guidance on how to set up the 5.1 monitors and incorporating my Dynaudio BM12As for stereo mixes would be great. In one of the photos attached i moved the Dynaudio monitors on stands away off the desk and all the bottom disappeared. Considering the carpet on the floor and reverb time should i utilize the existing curtains behind the monitors or do something else. It obviously makes a difference when the curtains are drawn. Im curious as to where to place all of the speakers ( And treatment above speakers) in the room considering the shape of the room and the existing bar at the back of the room. Photo attached. I have about $1000 to start with. Thanks in advance for any help. Tony