the bolt/studs- you use 4 they go into the turbo (where the exhaust butts up to) thats if you are removing the old studs when you remove old nuts to remove old dp (one of mine snapped when i removed mine so good you got new ones just in case)
gasket with 4 holes - this goes between dp and turbo (slips onto bolt/studs that stick out the turbo)
nuts - after putting dp onto turbo, tighten nuts to hold it on!!!!
3 hole gasket - might fit between both pieces of the dp