Using CDN is usually faster as the browser loads the cached version of file extensions
If downloading manually/ locally then only the .min version of both the JS and CSS files are needed, not the whole folder - place the /min files in your own JS/Style folders naturally - and the complete version of the fonts folder. Don't forget to make a jQuery file locally as well by downloading the latest version!
Containers
Add 15px padding
Columns
The default grid has 12 columns
just a good tip tip to know: Columns have a negative margin of -15px so remove any padding from containers
The class calls for col-SIZE-SPAN : column-when it stacks like 'm d'-how many columns
They also have a default of 30px gutters (15px on each side)
Extra Notes
Look further into clearfix class and responsive utility classes for difficult layout issues
Offsets can potentially effect layouts in unexpected ways so be careful!