How to download antegros if win 8.1 is already installed?

Question

linux

Win 8 was installed. Then, following the instructions , I installed antegros.
But on startup it loads win.
I tried to use a flash drive to restore the Linux bootloader. As written here
But when you type: grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Antergos-grub
Gets out:

WARNING: Failed to connect to lvmetad. Falling back to device scanning.
grub-probe: error: cannot find a GRUB drive for /dev/sdc1. Check your device.map.
done

They also write that it is necessary to disable secure boot in the BIOS, but it is not in the settings.

bios screenshots

Prompt how to configure loading of two systems.

Answer 1

grub is not installed or what?