Series detail is the main page where you can see a series and all the entities related to it. As you can see below, there are a number of controls. To start, the series cover image is displayed along with the title of the series. From the buttons you can Continue Reading, Edit Series, Download the whole series, or add/edit your rating and review.
Below this section is the collection and type area. Collection tags can be clicked to view all items in that collection. To start reading you can either click the individual volume or chapter or let Kavita resume you where you left off by clicking "Continue". Continue will open the last chapter that you have progress on or the next (if the last one was finished). If you don't see Continue, this means you haven't started reading yet. Press "Read" to start reading from the first volume or chapter.