The Jupyter Notebook below walks you through on the process how an RGB composite can be created from raw Sentinel-2 images.
Raw images can be downloaded from https://scihub.copernicus.eu/ after a free registration. Please note that activation of your account can take 24 hours!
I hope that I have not scared you off from programming/image processing too much. For those who got excited and want to try out and play a little bit with the code, the whole package with the Jupyter Notebook and the sample satellite images can be downloaded from the following GitHub link.