Mission : Just one of the missions you can accomplis.
This will display the rewards for completeing the mission.
Click this to start the reweard. Once completed, click the icon to claim the rewards.
Free refresh : Displays the next time your free refresh is available once used.
You can speed up the refresh time buy clicking it after use.
Missions : This is where you go to access game missions.
Acheivement : This is where you can access your rewards once completeing certain objectives.