A quick overview on how to use QGIS to help determining coverage and help on design:

The PDF Manual : Qgis Mapping Network

The Power Point : QGIS Mapping Network

All the guideline are made for the version 2.18.16  which can be found here:

For WIN 64 : http://download.osgeo.org/qgis/win64/QGIS-OSGeo4W-2.18.16-1-Setup-x86_64.exe

For WIN 32: http://download.osgeo.org/qgis/win32/QGIS-OSGeo4W-2.18.16-1-Setup-x86.exe

Last Update 12/10/2018