All players get their own number on the board. The players first need to score on their own number. Select the game option if any field or only single, double or treble are allowed. Also select the score needed to become a killer.

Tap the field on the board you hit with every dart and then register your hits. If you manage to tap the wrong field, click the RESET button and retap the correct fields for your hits.

When players reach KILLER status, they instead try to score on the other players number to get them down to zero. If a player already have 0 points you need to hit them once again to kill them.
When you're a killer tap the fields you hit for the other players numbers to reduce their points.