How do you change head on stihl weedeater?

To change the head on a Stihl weedeater, first ensure the trimmer is turned off and disconnect the spark plug for safety. Use a wrench to remove the old cutting head by turning it counterclockwise. Align the new head with the spool, threading the line as per the manufacturer's instructions, and secure it in place by tightening it clockwise. Finally, reconnect the spark plug and you're ready to go.