You get coins from killing more and more players, if you want more coins you can always get a rank from the PikaNetwork store
Also try and win a lot more games because it gives you much much more coins as well as more xp. To earn more coins it's worth buying a rank because you can earn a lot more coins also xp and much better kits with the rank you buy
If you would like to upgrade your rank head to the store here:
(These ranks support bedwars and skywars)
Hope this helps you mate