Open a terminal, and copy and paste those commands, one line at a time:

wget -q "http://deb.playonlinux.com/public.gpg" -O- | sudo apt-key add -

sudo wget http://deb.playonlinux.com/playonlinux_trusty.list -O 
/etc/apt/sources.list.d/playonlinux.list

sudo apt-get update

sudo apt-get install playonlinux

PlayOnLinux will be installed. Open it from the "Games" submenu, and install any game you want (You'll need either the original disk or a GOG.com installer)