Click the icon next to the mini map to access to the map layout screen.
Click on the "World Map" icon on the bottom.
Click the "Search" button on the bottom right, enter the "server ID" then click Go.
On the server information screen, make sure you can see the "Server Transfer" button. Click on it to go to the next step.
If you cannot see that button, your current server and the destination server are in different physical region (EU/Asia/America). You would need to contact TopWar to help you switch the region.
If all the conditions meet, the "Apple to transfer" button will light up and you just need to click on it to proceed with the move.
You can always buy the transfer ticket by clicking the (+) button next to the required ticket number.
Click on the (!) icon next to the "Combat power cap" text to see your calculated CP.
You can buy transfer tickets in: