What the buttons on the Jabra Evolve2 40 do
Volume + and -
The two outside buttons on the headset itself are located on the right earpad. The top one increases speaker volume, the lower one decreases
The button between the two volume controls pauses and plays whatever media is playing. Youtube, Spotify, Netflix, etc.
Located on the outside of the right earpad, right at the base of the microphone boom. You use this button to answer/end softphone calls.