you need theese pieces.
1.put the holder in the small black piece like om the picture.
2.put the gray brick with a stud in the middle on the black piece.
3.put on the light grey brick.
4.put on the round, grey brick.
5.put on the black pieces with studs on the side in front of the holder.
6.put a stick in the holes before you put on the arms.
7.put the black piece in the hole under the grey, round piece and put on the lego technic things on. congratulations! you have now buildt your own quad blaster ready for battle!