In that case, you would need to setup clientlib.
You can also “proxy” your clientlibs. This means that you place your clientlibs in /apps, but will be served via /etc. To enable this you need to add the property allowProxy to your clientlib.
https://docs.adobe.com/docs/en/aem/6-3/develop/the-basics/clientlibs.html#Locating a Client Library Folder and Using the Proxy Client Libraries Servlet