Currently, it is not possible to upload templates. For a site to work in Yola, it needs to be built starting out with one of the templates available from Yola. We have been working hard to expand our template selection and allow for more customizations with our current styles. We suggest using one of the styles in Style > Change Template and select Responsive.
These styles, in conjunction with our Style Designer, are our most flexible styles yet. You are able to control almost every element on your site.
If you go to Style > Designer, you will see a wealth of options available for you to tweak your site. Please have a look at our tutorial for helpful tips: Personalize your Style.
In addition, if you are a Yola Silver or Yola Gold customer, you have access to the Site CSS feature which allows you to customize your site even further.
We hope this gets you headed in the right direction, and we're happy to help you along the way.