Rooting and installing a custom recovery on the LG V10, T-mobile network is fairly easy; I can guarantee as I've tried this on my LG V10. First of all you'd need to download the ADB Setup, and then you'd need check the oem unlock and the usb debugging mode on your V10. Now comes the time for connecting V10 with your laptop via a USB cable. Now open up the cmd and enter few commands mentioned. Now copy the TWRP recovery files over to the ADB folder. Your V10 handset will now boot into the custom recovery mode where you can get ready to install your SuperSU file. Reboot the v10 device and follow the first few steps to get ADB set up on your computer again. You’ll need to enable the Developer Options menu again. Don't forget to read the whole guide here http://techchomps.com/how-to-root-the-lg-v10-t-mobile-and-install-a-custom-recovery/ and also to share this post!

Caution:
1. Use this guide at your own risk, I'm not responsible if anything gets wrong.
2. Please follow the steps appropriately and chare your phone to sufficient level(s).
Adieu!