There are a few ways to begin following a piece of content, a person, or a place in the community. Here are some easy ways to get started.
To stop following something, go to the item, person, or place (by either tapping it from a stream or searching for it under the Find tab), and then tapping the Follow icon. From there, select the streams from which you want to stop following the person, place, or content item. You will no longer see the checkmark next to that stream(s), and you will no longer see updates for that person, place, or content item in that stream(s). Those updates will still appear in the All Activity stream, however, because that stream shows all public activity in the community.