LG FR74 Owner's Manual page 13

Starting the LG Heart Rate Earphones 13
5. Secure the ear set back over the ear as shown in the illustration.
2
6. Adjust the length of the line of the Ear set using the Peg as shown illustrated.
7. LG Heart Rate Earphone
,
Note
When you wear the Ear set incorrectly, it can affect measurement accuracy.