Tom
You have:
1) the 18.5 WSM
2) briquettes
3) ATC.
IF YES, I usually like this (I have the 22 WSM w/briquettes w/ATC):
1) I put a thin layer of briquettes all over the grate
2) I put 1 split of smoking wood
3) I fill up the ring with briquettes
4) I assemble the WSM w/o water in the water pan...