example readme: complete jupyter notebook view instructions

examples/README.md

@@ -1,5 +1,8 @@
 # freesurfer-volume-reader examples
 
 ```sh
+pip3 install --user pipenv
+git clone https://github.com/fphammerle/freesurfer-volume-reader.git
+cd freesurfer-volume-reader/examples
 pipenv run jupyter notebook
 ```