If you are still in trouble, you should know that old (Legacy) BIOS has different logic from new UEFI.
In UEFI, you don’t need to decide where to install MBR. UEFI manages all installs no matter what disk (not partition) you installed Linux on.
Since you are dual booting with windows and windows is already installed in UEFi mode, you are advised to install Manjaro in UEFI mode as well. Of course you should verify that Secure mode is disabled.
As a matter of fact, I think you had done it well in your first attempt. You just had to select the Manjaro option (what you saw in the first drive).
So, you install manjaro as you did and don’t select the sdd for boot but look for Manjaro. You said you booted in Manjaro. It means the install was OK. Then after first boot in Manjaro, you update your Grub and it will find Windows and will add it in the boot menu.
From terminal run
After reboot you setup UEFI to always boot Manjaro, and you select Windows from Grub menu.
I hope I helped.
PS: This is a common thing and there are many forum posts with many scenarios and also Tutorials and Wiki pages.