Someone shared this link in our Matrix room. I don't remember who that was. I thought it should go here in our discussion forum. Most people who are interested in Mapping and GIS would find this useful. I am finding it useful.
It's an open online course from Pennsylvania State University on Open Web Mapping using FOSS tools. I encourage everyone to read through each chapter of this course, so that we can better understand the usage of tools in mapping and kinds of mapping that we plan for.
Course Link: https://www.e-education.psu.edu/geog585/node/519