Teaching the use of GIS software is beyond the scope of this website. Links will be provided in the "Using Data" section to training material available on the internet for using QGIS the open source software that that is referenced in the website. There is more information in the section "Open Source" on downloading the software.
QGIS can load data in a number of formats but the most common are probably "shapefiles" and spreadsheet tables. The shapefiles are loaded directly while spreadsheet tables and other formats often require some kind of formatting. Data for use in GIS analysis will be listed under the various headings along with national and subnational data. Data which does not fit into the designated categories includes the basic global national and subnational outline files, for which sources will be given below. Also given below are links to two sites which provide shapefiles containing detailed current data from OpenStreetMaps (OSM). The OSM mapping is done by volunteers and completeness of areas mapped varies from country to country--much progress has been made recently in the mapping of developing countries.The sites selected for the various sectors provide global country-level data or at least data for a number of countries.
Outline Maps--There are many sources of "shapefiles" which provide global, regional, national and sub-national outline maps onto which other data can be superimposed. A selection of sources of this type of data are listed below.
DIVA-GIS -- Provides shapefiles of administrative areas (usually two or three levels), as well as vector or raster files for inland water, roads, railroads, elevation, land cover and population. The files are available for almost all countries (note that Sudan and South Sudan are not separated) . The downloads are available at http://www.diva-gis.org/gdata.
GADM-- The GADM Database of Global Administrative Areas provides downloads of country shapefiles with several layers of administrative areas. The data can be downloaded by countries or in a single file for the whole world. The data is available for academic and non-commercial use. The downloads are available at http://www.gadm.org/.
Thematicmapping-- Thematicmapping.org makes available a world map with country borders-- the attribute table includes ISO and UN country codes and other data, some of it rather dated (Sudan is not divided). Two versions of the shapefile are available at http://thematicmapping.org/downloads/world_borders.php.
Statsilk--This site provides links to country and sub-national outline shapefiles as well as outlines for individual countries, and links to other GIS resources. Click http://www.statsilk.com/maps/download-free-shapefile-maps.
Natural Earth-- Provides a shapefile with point data for the world's main cities. Click http://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-populated-places/
Nordpil-- Provides population data and projections to 2050 for for the world's major cities--the data is available as a spreadsheet or shapefile. Click https://nordpil.com/resources/world-database-of-large-cities/.
OSM data maps-- The two links below allow the downloading of up-to-date data from OpenStreetMap mapping.
Geofabrik -- Geofabrik provides shapefile downloads refreshed daily of selected data (roads, buildings, residential areas, etc.) for all countries from Open Street Maps. Data is available at the country level as shapefiles for most developing countries as well as some smaller industrialized countries. Data for larger countries is often provided only at lower levels of administration--for example states or provinces. The organization of data can be a bit confusing. For example, the main menu allows you to select country data for individual continents by clicking on the continent name. If you click on Africa you will find a list of files for each country with a shapefile. If you click on North America you will find no shapefile for Canada or the US but shapefiles for all individual US states-- to find the shapefiles for the individual provinces of Canada, you must however select by clicking on Canada. The same rules apply to the other continents. Note that mapping on Open Street Maps is done by volunteers and the completeness of coverage--particularly in rural areas-- varies from country to country. The main menu is at at http://download.geofabrik.de/ .
Humanitarian Open Street Maps (HOT)--The HOT export tool (https://export.hotosm.org/en/v3/exports/new/summary) allows users to draw the areas and identify the data they wish to download. The site provides more choice than Geofabrik but may require several downloads to get complete coverage of a larger country. There is no charge for the data but users have to register before they can request downloads.