Welcome!
Why do you want to build bass traps? What are your complaints? Have you measured the room? Recommend measuring with REW (Room Eq Wizard) or Dirac with calibrated microphone. Can't solve a problem you haven't defined.
Suggest reading Floyd Toole's "Sound Reproduction" 3rd edition as the consummate audiophile primer to learn how speakers behave in-room before spending money/sweat elsewhere. Knowledge is power. In the book, you'll be lead to the use of carefully placed multiple subwoofers (I have three) as the second step (the first being finding the proper room, bigger is better, well shaped, and insulated). Typical setups act like a hand moving back and forth in a shallow tub of water. The waves hit the end and bounce back. When they encounter the next wave they either cancel, double up, or interfere with each other. In your room that translates into peaks/dips of up to 30 dB at different combinations of frequencies and locations.
Absorption is the next step (mostly as a band-aid for sick rooms). I use ten GIK 2ft x 4ft 244 panels (six "full range" and four "limited" range, <80 Hz) in my 8ft x 13ft x 21ft (an ideal room). Very effective in lesser rooms and not expensive. GIK uses Owens Corning 703 high density fiberglass, the secret to their effectiveness. Glanced at the Acoustic Fields activated carbon, but the concept doesn't make sense to me as for instance the size of a 100 Hz sound wave is over 11 feet versus the tiny size of activated carbon particles. Plus they're expensive and bulky. Check out specifications for any absorptive products/materials.
Bi-directional (not linear slots) quadratic diffusors are the best type to be used, but can only effective down to roughly 1,100 Hz due to the depth of the panels and the physical size of sound waves. Most diffusors aren't bi-directional and aren't made of acoustically opaque construction. Thankfully good diffusors are easy to make out of painted wood (but heavy). Here's a good recipe: prerecords.com/diffusor.cfm
