Readme updated

README.md

@@ -23,6 +23,28 @@ Different to SAMSIM2.0, this version does not need to be recompiled for changing
 Additionally, the option of initializing the model with prescribed sea-ice conditions 
 has been added. 
 
+You should be able to either use the executable file to run the model or compile it yourself. Both workflows are described below. 
+
+## Running the model with the pre-compiled executalbe 
+If you don't want to complie the model on your own computer, you should be able to use the provided executable (samsim.x). 
+This way, you don't need to have a fortran compiler on your local maschine. You only need to have python installed. 
+
+To run the model, you simply have to build a config.json file for the testcase you want to run by running the 
+respective build_config file with python.
+
+Now you can simply run samsim by running the executable file. Windows user will need to run it from their Linux 
+sub-system which is activated by typing into the console :
+
+````bash
+bash
+````
+
+Now you can run the model from the home directory (samsim3.0) by running the executable. To do this type:
+````bash
+./samsim.x
+````
+
+
 ## Compiling the Model
 
 You need a Fortran compiler, preferably gfortran, which can be installed as follows: