Assume you have a debian based system (Raspbian, Ubuntu Mate, Ubuntu LXDE etc) ready,
Now in /etc/apt/sources.list add
deb http://packages.erlang-solutions.com/debian jessie contrib
Then
wget http://packages.erlang-solutions.com/debian/erlang_solutions.asc
sudo apt-key add erlang_solutions.asc && rm erlang_solutions.asc
Finally
sudo apt update
sudo apt-get install erlang
Now open terminal and execute,
erl