When you explain your issue be specific as much as possible and avoid general terms.
Also don’t use terms you assume is what you see, but explain it in long sentences (with proper linefeeds). 
Which instructions did you follow, there are many.
- A bios screen looks very different as any other thing you will see on your screen.
Are you 100% sure it is the BIOS aka setup screen of your hardware? - It all depends on how you installed an operating system, it does not always show up in the boot section inside the BIOS interface.
- It could be listed in the boot menu, but you need to select that outside of the bios interface, usually using a function key.
You might have done wrong things and erased your Win… and left with a system unable to boot any OS.
Since we are no telepathist or able to view from your eyes, you need to provide concrete info.
- Boot using your LiveUSB of Manjaro
- Provide the output of the commands @megavolt above asked for, to begin with.
See this topic on how to provide various info, especially in a way that is correctly formatted on the forum: