Installing Linux on the EVOC P775TM1-R:
If you are dual booting, install Windows first, and partition from there with a tool such as Minitool. You'll only need two partitions, one for root and optionally, a small one for swap (say, 8GB). Partition them as appropriate, and when done, reboot into the UEFI menu and ensure that:
(a). Secure boot is disabled (otherwise you won't be able to load up proprietary drivers needed for the Nvidia GPU).
(b). Confirm that you're booting in UEFI mode ONLY. This is the default. CSM should remain disabled. Here's why.