Before you upload your SVG, you're going to need some classes to target inside your SVG. To do this, open your SVG file in the code editor of choice (I use Sublime Text). You will see each element within your SVG file written in XML code. Each little part of your SVG has it's own bit of code, so it's up to you which ones you want to target. It's in here that you'll place your new classes on each element you want to target.