The assembly instructions came in a booklet with the juicer. If you misplaced it or it was handed down to you....The main part that collects the pulp and pours the juice into the included container goes first, then the colander metal part goes in next, be careful NOT to touch the inside metal piece as it’s very sharp, grab from the outside and if need be use a potholder glove type, using the guided white arrows on this piece, align with the center main piece and push down until it snaps into place. Next, place the top large piece which has the tube like protrusion where the fruit/veggie will go in. Depending on how large your pieces of fruit/veggie are you will need to choose whether to use both of the pieces that go into the tube. One piece can be used to push any fruit that hasn’t quit made it fully through the blade.