Theme – Genesis: How to change width of sidebar and remove whitespace

Hello,

I’m relatively new to WP and do not know much about CSS. I need to remove some of the whitespace on the main pages on my site and change the width of the primary sidebar. The problem is that the primary sidebar shows up at the bottom of the page.

An example is: https://www.healthinfotexas.com/ehr-technology/

Thank you in advance for your help!!

Lloyd T.