The Overview consists of a table of entries. If there's a lot of news items, you'll be able to page through them and set the amount of news shown on one page to your liking. Also, you can sort them by each column, simply click on the column's header.
Most importantly you can filter the news. There's two filter options on top of the table. The status filter initially is set to only show scheduled news or those pending approval. You can change this filter if you like to see which news had been scheduled but now are on status published, or which news have already reached their expiry date and have the status expired.
All these settings will be stored for you, so if you visit the overview a second time, everything will be like you left it - as long as you don't flush your browser's cache.
The input field on the top left is a combined search and filter field. Enter whatever you are looking for, and the table will filter down to show only those entries matching your criteria. You could for example enter an authors name, a space name, a date etc. Probably it will be mostly used to search for keywords contained in the title, when people want to check on the status of a specific news item.