After forking the Pageflow repository to your own GitHub account, create a clone on your machine:

$ git clone git@github.com:your-account/pageflow.git
$ cd pageflow

Install dependencies:

$ bundle install
$ yarn install

Add a remote named upstream to be able to pull changes from the codevise/pageflow repository:

$ git remote add upstream git@github.com:codevise/pageflow.git

Now you can update your fork to stay up to date.