Remove the battery line before changing the Ego string trimmer line. This will increase safety. Now, press the release tab on the spool retainer and remove it by pulling it out. Next, remove the spool and clean the inner surface of the spool base. After that, it's time to take a 16" of the new cutting line, then fold it in half. Next, hook the folded end to the spool on either side and wind it in the indicated direction. Once you are done with winding, place the ends of the lines in the two opposite ends of the spool. Then put the reel in the spool retainer, pull the lines to release them from the notch in the eyelet. Now snaps down the retainer so that it places evenly.