Add instructions to run the python code

README.md

@@ -1 +1,59 @@
-# RDataFrame-Totem
+# RDataFrame-Totem
+---
+
+## How to run `distill.py`
+
+**Requirements**
+
+This script reads Totem data from `eos`, namely from the following path:
+
+```
+/eos/totem/data/cmstotem/2015/90m/Totem/Ntuple/version2/4495/
+```
+
+ Therefore, the totem project needs to be mounted and accessible for the user.
+
+### Using pure python from a terminal
+
+1. Clone this repository:
+
+```
+git clone https://github.com/JavierCVilla/RDataFrame-Totem.git
+```
+
+2. Prepare the environment
+
+  - The code requires `ROOT-6.14.00` or greater and `Python`.
+  - Simplest way to fulfil this software dependencies is using the LCG Releases available through CVMFS.
+  - The following command will setup your environment with these packages ready to be used:
+
+  ```
+  source /cvmfs/sft.cern.ch/lcg/views/dev3python3/latest/x86_64-slc6-gcc62-opt/setup.sh
+  ```
+
+  - Alternatively, your own `ROOT` and `Python` installation can be used, in which case you should ensure the python `ROOT` module is properly configured in your environment so it can be imported:
+
+  ```
+  python
+  >>> import ROOT
+  >>>
+  ```
+
+  - If the previous import failed, your `PYTHONPATH` may not be properly set. The easiest way to configure the environment for `root` is using its own setup script:
+
+  ```
+  source /your/path/to/root/bin/thisroot.sh
+  ```
+
+3. Run the code:
+
+```
+python distill.py
+```
+
+### Using HelixNebula
+
+- Init a session in Swan HelixNebula and select the bleeding edge software stack, this is the only one that currently provides `ROOT-6.14.00`.
+- Just copy `distill.ipynb` to your Cernbox space or to your SWAN instance in HelixNebula.
+- Open the python notebook and execute the cells.
+- HelixNebula already provides the needed environment configuration as well as access to the `eos` files.