How can i play rank in pbe there is only normal

There is not ranked. PBE is a server created by RIOT to test any changes they make in the game before they get them to live. So anything that has to do with competitive games isnt implemented in there. That mean no ranked. This is also the reason you will see many picks, builds etc. that would be considered troll in the live servers and would get a ton of reports. Like, someone i saw, who played full MS Janna in mid when the gave her %ms damage increase from her passive.