Studio Themes determine the look and feel of a website. Themes group together all the styling meaning you can run different websites side by side. Studio Templates require a Theme and Pages require a Template so effectively every page runs from a Theme.
Start by installing a Theme: install-a-studio-theme.md or copying a Studio Site template: setup.md
If you're looking to create Themes you'll need our Studio Theme Publisher: studio-theme-publisher.md
{% embed url="https://youtu.be/qSCmqcmnDec" %}