First off, I salute you for this Ahj, cuz sometimes a prewritten tutorial can be replaced by a collection of all the good threads on the subject with a brief description of what to look for in each - and on that note, I present my assembled collection of Acoustic Treatment
Basic acoustic treatment help?
If you are not thinking about treating your room ...
Some Advice on DIY Bass Traps
(Info about 703 vs. 705, esp. on pg. 2)
(Good info on DIY bass traps)
Hope it helps!