Depending on what type of machine you have, you will have generally a slot in the top of the presser foot that slides onto the shank of the machine. There is also another little gizmo sticking up from the bottom of the foot that has to sit onto the screw that holds your needle in place. This is what makes the foot move at the same time as the needle and there is also another piece in the presser foot that will come down and hold the fabric in place. Sometimes, dropping the feed dogs makes this easier. Slide the foot onto the shank, but tilt it slightly to get the extra little piece to rest on that screw. then tighten it in place and raise the feed dogs again. Not hard but it might take some wiggling of the presser foot to accomplish tis. Good LUck :!: :-)