I've made several videos already (and there are countless more online) about the Topic Marker and how to use it.
The Topic Marker is used for marking the topic of whatever conversation you're currently having - or an individual sentence. There are some things it's used for, and others it's not. This video is not going to be an explanation of how and when to use the Topic Marker.
Instead, this video is about what the feeling of the Topic Marker is, to help you better understand when you should or shouldn't use it.