The instructions usally come in the box of a good brand filter, but it's simple to change. First you need to get the tool to remove the top of the housing. KD makes a nice one, you could use a screwdriver in a pinch if nec. Unsrew lid, place some rags around the housing to catch drippings. remove beveled o-ring from top of filter housing paying attention to the way the bevel is pointing, slowly pull filter up out of housing. Next lube new round o-ring w/fuel an place on filter. Slowly push filter into housing lube and install beveled o-ring flat side down and bevel out if I remember correctly, and re-insall lid. Ck for leaks.