In addition to what has already been written about seating the needle and threading... The bobbin goes into the bobbin case such that when you pull the thread the bobbin turns counter-clockwise when looking at the bobbin. Also, DO NOT turn the balance wheel backwards - only towards you (counter-clockwise when looking from the balance wheel end of the machine). That will definitely cause thread jams. Also be sure the needle is fully seated against the stop. Good luck!