Default Root Z2

So, i finally made a decision so root my Z2 But first i wanna ask some stuff.. What do i need to know first of all ? All i want root for is so i can copy apps to my sd card thats it =) But then again.. Once i root can i delete it incase i need my warranty back?? What is the easist way to root Z2 ? Do i need a custom recovery ?? What can go wrong rooting Z2 ? And i assume i got locked bootloader from start? Regards.