In the game Paper.io, you use your mouse or arrow keys to move your block. You can expand your territory by creating circles complete with your color area. You can kill other players by stabbing them in the tail while they are drawing outside the territory.
Tips
To be able to conquer the game Paper.io you need to understand the principles of playing and how to control your color block. You can watch video tutorials to get more tips from experienced players.
A safe bet for you is to start small. Avoid being too ambitious and trying to conquer too much territory at once, as doing so will leave you vulnerable to enemy attacks. You can be hit by guys who can cross the line and kill you.
Waiting for easy opportunities to destroy the enemy. When you see the opponent moving out of his color area, you can attack the opponent to destroy him.