RCA Timeline renders only on the site front end where you publish the module instance. There is no administrator preview beyond standard Joomla module preview workflows.
Layouts output HTML and CSS scoped to the module chrome. Heavy template overrides on mod_custom or article layouts do not affect timeline markup unless you override mod_rca_timeline tmpl files in your template.
You may publish several RCA Timeline modules on different pages with different categories and styles. Each instance loads its own layout CSS through Web Asset Manager based on the selected style.