Can't install Manjaro Cinnamon - Bootloader

I’m about to install Manjaro Cinnamon, but I get an error message. I am not very familiar with Linux, I have long experience with Windows, I just want to try something new.

I’m installing Manjaro Cinnamon on an external hard drive that I’ve erased completely. The boot loader is on my Windows C:\ drive.

Here’s the problem:

Installation Failed
Boost.Python error in job “bootloader”.
Command ‘grub-install --target=i386-pc --recheck --force /dev/sda’ returned non-zero exit status 1.
Installing for i386-pc platform.
grub-install: warning: this GPT partition label contains no BIOS Boot Partition; embedding wont be possible.
grub-install: error: embedding is not possible, but this is required for RAID and LVM install.

You most create a BIOS boot partition in partition step on installer.

I will try that.