I think you can use goo manager app to install twrp as well. Then just power down and you hold volume down + power, the cap lights will flash, once they are done flashing release the buttons and press and hold them again and it should boot into the bootloader where you can select recovery. Kind of weird but it works. Also, your phone will boot normally once after you install a recovery for some reason even if you try to get in. After that you can get it no problem.
The videos in the regaw root method show everything really, really well. I suggest watching one.