To change server is a good think to know how to do. You can look for looting sites, spy on hqs to see power, to find trucks in special servers to raid and find bounty to loot.
Find the magnifing glass in main screen to the left under radar symbol.
click on it and you get a bar high up at screen.
You will get this look on your screen. Change the numbers to the left in the bar (your server number is there by default, 178 in my home server) change to the number you want to go to.
when the number is in , click on the magnifing glass to the right in the same bar.
Now you are in the server you wrote in. You can see the number of the server in the bar that you now have on the screen. see my pic below to see the bar)
