If you are smoking your own trout, do not try it inside your house. Do it outside.
Using your hands, rub the fish with rosemary and salt.
If you have a smoke oven: Fill the smoke oven with wood shavings, and ignite. Smoke the fish for approximately 20 minutes.
If smoking in a large pot: This rather unconventional way of smoking works just fine. Use a large pot and a stick. Attach the fish to the stick, long enough to rest across the top of the pot. Place a large pot over high heat (on a grill or over direct flame), and fill with wood shavings. Hang the fish from the top of the pot, and place the lid carefully on top (you will not be able to cover the pot completely). Let the fish smoke for 20 minutes, and turn of the heat. Leave it for 5 more minutes.