For installation Erlang 17.3 on Ubuntu 18 you should do the following things: Enter in the console next command:

• Download the tar file:

wget http://erlang.org/download/otp_src_17.3.tar.gz

• Extract the tar file in directory where you download the otp_src_17.3.tar.gz:

cd '/home/yaroslav/otp_src_17.3'
tar -zxf otp_src_17.3.tar.gz

• set export ERL_TOP your 'pwd' path:

export ERL_TOP= pwd

• Basic dependencies:

sudo apt-get install autoconf libncurses-dev build-essential

• Other applications dependencies

sudo apt-get install m4
sudo apt-get install unixodbc-dev
sudo apt-get install libssl-dev
sudo apt-get -y install libssh-dev
sudo apt-get install libwxgtk3.0-dev libglu-dev
sudo apt-get install fop xsltproc
sudo apt-get install g++
sudo apt-get install default-jdk
sudo apt-get install xsltproc fop

• Or all dependencies in one line:

apt-get -y install build-essential autoconf m4 libncurses5-dev libwxgtk3.0-dev libgl1-mesa- dev libglu1-mesa-dev libpng-dev libssh-dev unixodbc-dev xsltproc fop g++ default-jdk

• install openssl version 1.0.2 for Ubuntu 18 (different version SSL is not compatible):

curl https://www.openssl.org/source/openssl-1.0.2l.tar.gz | tar xz && cd openssl-1.0.2l && sudo ./config && sudo make && sudo make install

• Configure and build:

./configure --with-ssl='/home/yaroslav/otp_src_17.3/openssl-1.0.2l'
sudo make
sudo make install

For installing older versions of Erlang and working with several at the same time I would recommend using kerl
If you need more fancy features you could also head for asdf which has a Erlang plugin (which runs kerl under the hood)