On any page which holds a list of more than 20 content items, you will find a filter right after the introduction. You click on this, and then Filtering options drop down. You need to check the checkboxes and/or put a keyphrase into the search field. Then you should hit the Search button, and see if you can find what you are looking for. If you still cannot find it, filtering can be repeated to narrow down search results.
See this short video on filtering.