I am jotting down the issues that I faced with Debian, in case I or any user requires it for future reference.
1. Change grub: Once Debian installs, it updates the grub and makes it the default distro. In case you have Ubuntu/Mint/Windows installed, you may like to have a different default distro. Steps are
Record the sequence where your default distro is (starts with 0)
Go to root terminal