so you want to make a DWC system this is how i do it i get a 5 gallon bucket from home depot and buy the lid to

i use 5" net pots so i cut a hole at 4 1/4" so it justs fits a little sung {spelling} then use a razor knife to klean the hole i also use the dobble air pump for one bucket with two air stones so here i go for you
step one get bucket with lid "my dog just had to be in the pic

"
step two i drill a hole for the air line in the bottom of the bucket "yes the bottom" i drill a hole the inside diamator of the air line and then fold in a v shape then stick it in the hole and it should not leak
step three get your air pump and your air line and use a t valve so it looks like this
step 4 do the same ith the air stones my stones are 6" long i use two
and that about it oh yea fill with water and check for leaks

if no leaks it should bubble just like this and your net pot should look like this
pic in order as i said and sorry for the long post