PrintQGIS follows a very rigorous release schedule in which new versions are released every three months and each 4th release is a so-called long-term release (LTR) that will be maintained for a full year (see the release schedule). Not too long ago, QGIS made a big step forward with the release of version 3.0 in February 2018. This was the first version based on Python 3 (not Python 2 anymore) and whose GUI was based on QT5 (not QT4 anymore). In this section, you will be downloading and installing QGIS on your computer and then familiarizing yourself with its graphical interface which has quite a lot in common with ArcGIS but also has some components that work a bit differently, such as the map composer part of the software.
In case you have already worked with QGIS in the past, it is still important that you make sure you have version 3 (or higher) of QGIS installed on your computer using the approach described in the following because of the switch to Python 3 and QT5 mentioned above and because the development we are going to do will require some further components to be installed. While there are some changes in the interface from version 2.18 to version 3, you can probably go through the familiarization part rather quickly if you have worked with QGIS 2 (or a previous version of QGIS 3) before.