FM2A85X Extreme4 CMOS Jumper and switch

some day i must replace bios battery and clear cmos,
(not quite sure in what order... maybe some one can tell me right way to do it)

asrock FM2A85X Extreme4 motherboard

-This motherboard has three smart switches: power switch, reset switch and clear
 CMOS switch, allowing users to quickly turn on/off or reset the system or clear the
 CMOS values.

-Clear  CMOS  Jumper  (CLRCMOS1)

why there is jumper and switch for same purpose,?

thank you
Can you tell what is right way to change bios battery.

there is many way to do it, what i found in the internet, but i`m sure that there is only one right way.