================== Step 1 =================
Screwing the two columns to the base plate
Drill 4 holes per column in the base plate (I know, there are 6 in the photo

).
Used these holes to mark and pre-drill 4 holes for the screws in each column.
Screw them woody bits.
================== Step 2 =================
Sliding the two drain pipes over the two columns
This is the hardest part of the whole project.
================== Step 3 =================
Screwing the top plate to the two columns
Do it the same way you fixed the columns to the base plate.
================== Step 4 =================
Finishing the top plate
I used a yoga mat (painted in black) to cover the top plate because:
- I had bits of an old one (don't ask)
- it is paintable and easy to work with
- it makes a nice padding for the speaker
- I had nothing better to use.

If needed, screw or blu-tak the door stops to the top plate.
================== Step 5 =================
Admire the result of your handy work