Please check out my video tutorial of it as well.
Step 1: STEP 1: ASSEMBLE THE TOP
As far as the Zip Ties goes. You want to fit the bottle you are using down the 6 1/2" pipe upto the Coupling. Place the zip tie on the rim of the bottle to see what the length of the zip tie you would need.
Assemble them in this order:
6 1/2" section of pipe
1/2" coupling (with zip ties taped to the coupling)
2" section of pipe
2" section of pipe (filled with hot glue)
1 1/2" section of pipe (goes on middle part of TEE)