Creating custom component in AEM SPA application involves
HTML markup creation in Frontend. In this case, it is Angular
Sling Model implementation with Exporter for Multifield component (Touch UI dialog for Multifield component) created in AEM.
Sample implementation of Multifield in AEM SPA is available in below link(refer comments section) for React. (But should apply for Angular too from backend standpoint. Just that way of retrieving the content and creating markup differs.)