Grab the last Hud and equip it (Add) on your avatar, your Celestial Butterfly Player account will then be automatically created.
You have to go to a Stump to be able to hunt and be 20m or less from it. The list of active Stumps is visible from the website in the Stumps Location section or from your Hud on the "Location" button (After the Net Button)
At the end of the Hunting Time (which depends on the equipped Nectar) a summary will be displayed in the chat giving you the name of the caught butterfly, its value, and the number of Xp earned. The xp allows you to level up and be able to access more possibilities in the game.