Turn off the weed wacker and disconnect the spark plug or battery
Remove the spool cover
Take out the spool
Remove any old line
Cut the new trimmer line to the correct length
Insert one end of the line into the spool hole
Wind the line evenly in the direction marked on the spool
Leave the required amount of line free at each end
Thread the line ends through the spool eyelets or slots
Reinstall the spool into the head
Replace the cover securely
Pull the line ends to confirm they feed correctly
Reconnect the spark plug or battery