Build something that works
Try setting up bootstrap columns of size 2 in a row.
Add additional rows.
One of the best tools for this kind of thing is Google Chrome's Inspect Element feature. If you right-click on the page and select 'Inspect Element', you'll be able to see the exact HTML and CSS styling that was used to create it. In this case, the footer is mainly built using customized CSS styling, so explore around and apply what you like to your own site!