you have 3 grams for 4 people so thats .75 grams each. Do a line in each nostril wait like a little then do 2 more lines. Then if you feel good wait till you start to comedown and repeat the process. If the 4 lines isnt enough just do more it takes about 3.5 grams to the face to OD so you have nothing to worry bout with only .75 for yourself