Can’t mount 1 disk out of a RAID 1 array

Hello, I can’t mount 1 disk out of a RAID 1 array, I tried using online guidelines, but when I run “sudomdadm --examine /dev/sdb3 /dev/sdb3” I get an error message. Then I tried “$ sudomdadm -A -R /dev/sdb3” and I get the error “mdadm: device /dev/sdb3 exists but is not an md array”. Tried mounting the drive “/dev/sdb”, got error “mount: /dev/sdb: can’t find in /etc/fstab”. When I looked in the drive, it says that it is a “Linux File system”. What am I doing wrong here?

Please check the link below
Mounting disk(s) from RAID 1 array for data recovery