More instructions

presentation/demo/README.md

@@ -1,6 +1,11 @@
 # FOSSGIS Seminar WS20/21 Interpolation Demo
 ## Setup
 The program requires Python3 with the GDAL module available.
+### Windows
+We recommend using [OSGeo4W](https://www.osgeo.org/projects/osgeo4w/) and then activating the python 3 environment within the OSGeo4W Shell using `py3_env`.
+### Linux/Mac
+Although not tested you should be able to install GDAL through [pip](https://pypi.org/project/GDAL/). As the program requires Python3, make sure to install the pacakge for Python3 and not Python2.
+We recommend 
 ## Instructions
 Use `demo.py --help` to list available options.
 ### Windows