To start with Jekyll, let's start with few simple steps:

Create a docs/ folder in your repository root folder and move all the project MarkDown documentation there; typically, the existing content in README.md gets moved (or copied) into a docs/index.md.
Create a docs/_config.yml, following Jekyll configuration docs

Checkout the FDC3 ContextData microsite:

docs/ folder (TODO - use master branch, when merged) in GitHub with Markdown source files
the documentation website on fdc3-context-data.finos.org

Running Jekyll locally

To run locally a Jekyll website, please follow the steps below.

Install a Ruby environment

It is strongly advised to use RVM or RBenv to install Ruby; below are the steps to install RVM on MacOS.

mkdir -p ~/.rvm/src && cd ~/.rvm/src && rm -rf ./rvm && \
git clone --depth 1 https://github.com/rvm/rvm.git && \
cd rvm && ./install
rvm install 2.5.2
which bundle #Should return a .rvm sub-path
which ruby #Should return a .rvm sub-path

Install gems needed for jekyll

cd /tmp
git clone https://github.com/pages-themes/slate
cd slate
rm -rf .bundle
./script/bootstrap
gem install jekyll-theme-slate
gem install jekyll-seo-tag
gem install jekyll-watch

Start Jekyll

cd docs/
jekyll serve --incremental