Install QGIS on Linux

The official installation instructions are HERE

a few other how to pages

QGIS 2.18 with GRASS and R on Ubuntu

QGIS 2.18 on Debian / Ubuntu

Linux installation videos

QGIS 2.18 Ubuntu no sound, Youtube Video, 5m53s

QGIS 2.12 Ubuntu en Portugués, Youtube Video, 5m7s

QGIS 2.18 Ubuntu en Portugués, Youtube Video, 11m54s