By default, you have two variations, the Original which acts as the control, and the Variation where you will make your changes. You can easily add more variations by clicking Add variation or make a copy of a variation by clicking Duplicate. You can also rename the variations if you want. You perform all these actions by hovering the variation and then selecting the preferred action.
To start coding your project make sure you are on the correct variation and then click on Show code to open up the code editor.
If you do not wish to code your changes manually you can try out the WYSIWYG-editor. You can make simpler static changes with this. Remember to preview your changes and to set and test Audience so that the changes only happen on the page(s) you want. Also, remember to set up Goals for the project before you activate it.
The CSS is written as a standard CSS file and is added as an external CSS file in the head tag on the website. These changes will happen instantly as soon as the Symplify implementation script has loaded.