Some tutorials will be mostly demos and you can participate by just watching the presenter explain code and run commands.
Other tutorials will be more hands-on, where participants are supposed to execute examples themselves or even with coding exercises.
In those cases you'll want a laptop with Python and the required packages installed. Every tutorial contains a "how to prepare" section with instructions what software to install before the tutorial.
We recommend you go to https://www.continuum.io/downloads and get Anaconda. It's a free, fast and very popular way to get up-to-date Python and packages.
Miniconda is fine as well if you're on a slow network or low on disk space
... see here for
an explanation what conda, Anaconda and miniconda are.
It doesn't matter much if you get the Python 2.7 or the Python 3.5 installer for Anaconda or miniconda. With either version you'll be able to install Python and packages simultaneously with any of the Python versions 2.7, 3.4 and 3.5. If you're confused, just download the Python 3.5 installer.
Once you have conda available, please install one Python 2.7 and one Python 3.4
environment and learn how to use them here:
http://conda.pydata.org/docs/test-drive.html
Some tutorials (e.g. Gammapy and D3PO) need Python 2.7, one needs Python 3.4 (ctapipe) and generally Python 3 is the better language. Python 3.5 is very new and some packages (even Astropy) don't have a compatible stable release yet, so for now we recommend Python 3.4 (of course, if you're not low on disk space, additionally installing Python 3.5 just takes a minute).