City Data Roman Roads Roman Roads reproj Natural Earth
Collected PyQGIS/Python3 scripts containing:
10min dive into Python Network Analysis Network Analysis automation
Some Useful Resources
Intro to GIS and Spatial Analysis by Mainuel Gimond is a very good, cross-platform treatment that for sure will be of help when it comes to clarifying certain concepts.
QGIS Tutorials and Tips is a very good resources (attention: QGIS2, but for the most common tasks nothing changed).