Thanks for your posting! Do you mean the new template feature introduced with TR 5.2 or your custom fields? Both the templates and custom fields can be configured on a per-project basis and I would recommend reviewing the custom field documentation to learn more:
An introduction to the new template feature can be found here:
You can also configure your templates to apply to select projects only but please note that the default template needs to apply to all projects. I’m also happy to help in case anything is unclear or if you have any further questions.