This document describes how to integrate the popular front-end framework Twitter Bootstrap with XPages. The purpose is to provide developers an introduction to use Twitter Bootstrap in XPages development projects by building an actual application.
Below you can find a document/manual I started to write a while ago but I never finished (I guess there is no finish since new boundaries are explored every day). At least the document should give you a head start with using ‘raw’ (Twitter) Bootstrap in XPages. I also recommend you to take a look at the Bootstrap4XPages project on OpenNTF since this project offers lots of ‘out of the box’ conversions of components from the Extension Library (e.g. data view control).
Enjoy reading!
Kwintessential Notes 
Thanks for this Patrick – found the guide really useful and well laid out, easy to follow. I am now having fun converting our XPages apps to use the Bootstrap theme.