I have a password on my phone ,but i have never set one up before Xperia XZ Premium

[hovy]

So i purchased the Sony xperia xz premium and i did the set up.I downloaded facebook and i turned it off. Couple of minutes later i turned it on and a password appeared, but i had never set a password for this phone. I tried everything i could think of , but nothing worked. I cannot get into my phone , because of this password and it is really annoying.PLease help