Here's the recipe my family has used for probably more than 30 years:

1) fillet the salmon - keeping the skin on
2) cut the fillets into 1 1/2 - 2 inch strips
3) place the strips skin side down in a bowl
4) lightly sprinkle rock salt on the fish (no hard set amounts here - just a small handful)
5) sprinkle a handful of brown sugar on top (maybe a couple handfuls)
6) add more layers and do the same thing to each

Let the fish strips sit in the brine overnight. When you take it out the next day, the fish will be swimming in the moisture the rock salt extracted. Pat dry - making sure to remove any visible rock salt that didn't disolve. Then, place on the smoker racks for a couple hours to dry (sometimes a fan blowing on the full racks helps). Then smoke 3 - 12 hours (depending on thickness of fish). Smoke is only needed for about the first 3 hours - after that, not much penetrates, so why waste the chips. Hope this helps.

--Bank Angler