Hi Barbara Clements,
To make 3 column layout you need to follow bootstrap pattern: @see for the reference: https://getbootstrap.com/examples/grid/
http://www.w3schools.com/bootstrap/bootstrap_grid_basic.asp
//first content
//second content
//third content
2> Also you can try by adding this css on child theme style.css templates
body.home #columns .column {
margin-right: 30px !important;
}
Let us know how it will goes.
Note: Please use child theme to add custom css , so your changes will not lost on theme update.
Thanks