I'm using enterprise architect 15 to generate documentation via Publish/Report Builder/Generate documentation. There, I see I can use templates:
I want to use a template that I used in another project, but it's unclear to me how to properly export it from another project and import into this one.
You can export and import templates using the Reference Data Import/Export feature.
Configure | Model | Transfer | Export Reference Data
Select the the templates you want to export.
Configure | Model | Transfer | Import Reference Data
Make sure to select the Document Templates dataset to import.
An alternative to this import/export is to include the templates in an MDG technology file. See the manual for more info.