I use a large converted oil drum BBQ with a chimney vent. For a kettle BBQ you should use a smaller turkey.
Make a pile of charcoal on the left side of the BBQ, nearest the bottom vent and arrange the grill racks on the opposite side.
Insert the metal probe for the digital thermometer so that it is suspended over the area where the meat will be smoking.
Place a large heavy-duty aluminum hotel pan filled with water directly under the grill racks.
Light the coals and get them plenty hot.
Meantime, put the wood chunks on to soak, along with the rosemary sprigs.
When the coals are good and white spread them out flat, rearranging any black coals on top of the white ones.
Add about 1/2 of the wood chunks to the coals being careful not to put the fire out! Place the rosemary sprigs on top of the wood chunks.
Blow on the coals to get the smoke going and close up the lid, and open up the flue and chimney vent.
When the temperature inside of the BBQ reaches 200 F, open the top and arrange the turkey pieces onto the grill rack. Close the top and start the smoking process.
Do not open the top unless absolutely necessary for at least 45 minutes.
Add more fresh coals and the other half of the wood after 45 minutes of smoking.
Turn the turkey pieces over to get smoked on both sides.
You should only have to smoke the turkey about 45 to 55 minutes more.
Use a meat thermometer to check for doneness. About 155 to 160 for the breasts, and 145 to 150 for all the other pieces should do the trick.
Remove the turkey to a cutting board and tent with HD foil for 10 minutes before carving.