Adding a custom widget to an existing Experience Builder App

mikeb_mapb

I am using the experience builder and have created an application that I am quite fond of. I would like to add a time slider widget and have found some helpful documentation here: https://community.esri.com/t5/arcgis-experience-builder-questions/is-there-a-time-slider-widget-for-experience/m-p/555832/highlight/true#M915

Is there a way to download my current application into a developer environment and add the customized widget from there or do I have to start from scratch? I would like to get some more practice with javascript but I am looking for the most time-efficient solution.

I remade the app in Web Appbuilder but I really like the Experience Builder version more.

Thanks!