The Install New Software wizard allows you to add new software to your installation. To install new software:
Some of the items may be digitally signed by the company that provides them. This allows you to verify more easily that the features and plug-ins that are about to be downloaded and installed are coming from a trusted supplier. You may be prompted to verify digitally signed content once the signature is detected.
Warning: Because of the possibility of harmful or even malicious software, you should only download software from parties that you trust.