Turn off the weed eater and disconnect the power source or remove the battery
Remove the spool cover or trimmer head cap
Take out the empty spool
Cut the replacement string to the required length
Insert the string into the spool slots or feed holes
Wind the string onto the spool in the correct direction
Leave the ends at the indicated length
Reinstall the spool into the trimmer head
Thread the string ends through the eyelets or exit holes
Replace and secure the spool cover or cap
Test the trimmer briefly to confirm proper feeding