The only requirements are that you have an index.html file in the root of your template folder. Inside your template folder all other assets (CSS, font files, images, any other files you use in your template) need to be contained in one or more sub-folders. Use relative paths in your index.html file to link to your assets.

Here is one a sample template folder that works well:

├── css/
|   ├── yourStyleSheet.css
|   ├── anyOtherStyleSheetNeeded.css
|   js/
|   ├── anyJSFileNeeded.js
|   img/
|   |── anyImageFileUsedInYourTemplate.jpg

Depiction of the Upload New Article Template UI

Compress your index.html file and your assets directory into a single ZIP file and upload it to use in your magazine on the Publication > Design screen in the web console.

Remember, issues of TypeEngine magazines are downloaded in their entirety. This is because many people enjoy reading issues in contexts where there is not a network connection. For this reason, it is not advisable to rely on assets or dependencies that require a network connection. Always reference local assets in your template.