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 threads
Basic acoustic treatment help? (Great overview)
If you are not thinking about treating your room ... (Great overview)
Some Advice on DIY Bass Traps (Info about 703 vs. 705, esp. on pg. 2)
Bass Trappin (Good info on DIY bass traps)
Hope it helps!