Well, it depends on what you need from a download manager. In this case I will provide the easiest and most convenient method which is to use FlashGet. To understand why I choose this one I will list all the features which will greatly please you. The software is in download managing business for a very long time and it has reached a high level of performance because most of all it's a free software supported by the community, it can scan downloaded files using your computer's antivirus. It offers thread downloading to increase the speed of your downloads, browsers integration, a download basket to drag and drop links and network integration.
In order to get it, please download a package from the link I've mentioned and double click it. Upon installation you will have the ability to customize it in a few simple steps. It integrates automatically into your available browsers and it also has a network module for package capture. It can also save Youtube videos to watch them later.
The choice is yours but in my opinion, this download manager should fulfill all your needs.