The goal of this project is to gather tutorials and demo files for Lean beginners, allowing to see what it looks like without reading much documentation. Currently there is one such tutorial.
Of course you can look at this file online but the recommended way it to install Lean and get this project for local use.
If you have already installed Lean and mathlib in the recommended manner, and have access to a command line, then installing this project should be as simple as
git clone https://github.com/leanprover-community/tutorials.git
cd tutorials
leanpkg configure
update-mathlib