$ sudo apt-get update
$ sudo apt-get install erlang-cowboy-examples 

erlang-cowboy-examples is installed in your system.

Make ensure the erlang-cowboy-examples package were installed using the commands given below,

$ sudo dpkg-query -l | grep erlang-cowboy-examples *

You will get with erlang-cowboy-examples package name, version, architecture and description in a table

erlang-cowboy-examples package basic information: