Here is a tutorial that Grants.gov produced to help you navigate the website.
Use the Grants.gov search tool to find funding opportunities that your organization is eligible for and has a mission match for your organization. When you have identified an opportunity to apply for, you need to register with Grants.gov as an organization or individual. You should also check the funding opportunity for additional registration requirements specified by the grant-making agency.
Visit www.grants.gov to view all federal grant opportunities and to download additional resources.