ROS Installation issue on Ubuntu 16.04 [closed]

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Hi,

I am new to Ubuntu and hence have some installation issues. While I am trying to install ROS Kinetic, it throws me error saying that the source is not found. It also fails to download repository information.

W:Target Sources (-sc)/source/Sources) is configured multiple times in /etc/apt/sources.list:52 and /etc/apt/sources.list:53
W:The repository 'cdrom://Ubuntu 16.04.3 LTS _Xenial Xerus_ - Release amd64 (20170801) xenial Release' does not have a Release file.
W:Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
W:See apt-secure(8) manpage for repository creation and user configuration details.
W:The repository 'http://packages.ros.org/ros/ubuntu $(lsb_release Release' does not have a Release file.
W:Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
W:See apt-secure(8) manpage for repository creation and user configuration details.
E:Failed to fetch cdrom://Ubuntu 16.04.3 LTS _Xenial Xerus_ - Release amd64 (20170801)/dists/xenial/main/binary-amd64/Packages  
Please use apt-cdrom to make this CD-ROM recognized by APT. 
apt-get update cannot be used to add new CD-ROMs
E:Failed to fetch http://packages.ros.org/ros/ubuntu/dists/$(lsb_release/-sc)/source/Sources  404  Not Found [IP: 140.211.166.134 80]
E:Some index files failed to download. They have been ignored, or old ones used instead.

Please advise what I should do next.