Turn off the weed wacker and disconnect the spark plug or remove the battery
Let the trimmer head cool if it was recently used
Remove the trimmer head cover or spool cap
Take out the empty spool or old string
Cut a new length of trimmer line to the recommended size
Insert the line into the spool or align it with the head’s feed holes
Wind the line tightly and evenly in the correct direction
Leave the required amount of line exposed
Reinstall the spool and secure the cover or cap
Reconnect the spark plug or battery
Test the trimmer briefly and check that the line feeds properly