Storage in linux

Please help me in this question

While adding line /dev/vbd /mnt/data ext rw 0 0

The terminal is not responding once i type something and its not even getting exit from this space…
If possible please share a gif How to do this entire question

Thanks in advance!

@Afshan , you can use the vi editor and add the line /dev/vdb /mnt/data ext4 rw 0 0 and save using wq option.