There comes a time in many Android enthusiasts' lives when the urge to flash a custom ROM becomes too great, but that desire alone isn't worth jack squat without a custom recovery. The Team Win Recovery Project (yup, that's what TWRP stands for) is one of the more popular and reliable options out there, which makes it good news to for tinkerers with a Sony Xperia Z2 that support has landed for their device.
TWRP will let you flash ROMs and ZIP files, but before that, it will also give you the means to back up your device. Let's not forget how important that step is, as things can, and usually do, go wrong at some point or another.
Now that that brief disclaimer is out of the way, let's continue. The provided image file is from the 2.7 branch of TWRP, and you can flash it using fastboot. Instructions for doing so are available at the project's page below.