How to reset forgotten root password with single user mode- RHEL7 | CentOS 7

Very pleasent explanation

Why need to use in init=/bin/bash ?, second question : I saw different method for root password reset : rd.break console=tty in linux16 line and after that control X and change like mount -o remount,rw /sysroot; chown /sysroot;passwd root;touch /.autorelabel ; exit; exit, why this much need to do in RHEL 7 ?

Is there any difference between single user mode or maintenance mode and emergency mode ?

please upload RHEL7 certification videos

What are the common errors we get if we are using nfs server and samba services..?
Can you prepare a video on this...?