added switching to dev branch for installation instructions

README.md

@@ -21,15 +21,19 @@ TBD, see pyproject.toml
 
 Move to the folder you want to create download this project to.
 
-Clone the project from its git repository
+Clone the project from its git repository either via git or as zip, tar etc
 ```
 git clone https://gitlab.jsc.fz-juelich.de/esde/toar-public/toargridding.git 
 ```
-
-The handling of required packages is done with poetry.
-For installing them go to the new created directory and run poetry
+With git we need to checkout the development branch. Therefore we need to change to the project directory first:
 ```
 cd toargridding
+git checkout dev
+```
+
+
+The handling of required packages is done with poetry. So run poetry in the project directory:
+```
 poetry install
 ```