Turn off the trimmer and disconnect the spark plug wire or remove the battery
Remove the trimmer head cover
Take out the spool
Remove any remaining old line
Cut a new length of trimmer line to the correct diameter for your Stihl model
Fold the line in half if using a double-line spool
Insert the line into the spool’s center hole or anchor slot
Wind the line evenly and tightly in the direction of the arrows on the spool
Leave the required amount of line free at the ends
Thread the line ends through the eyelets or exit holes in the spool housing
Reinstall the spool into the trimmer head
Replace the cover and snap it into place
Pull the line ends to confirm they feed correctly
Reconnect the spark plug wire or reinstall the battery