All pretty easy to typeset, read the documentation.
For blocks it's pretty easy to set, for example
col-md-6 - 50% desktops
col-xs-12 - 100% on smartphones
col-sm-8 - 66.6% on tablets, etc.
Accordingly, the unit for different devices would look like this:
<div class="col-md-12 col-sm-8 col-xs-12">Data block</div>