Each grant has its own application process. Go to the grant category, which applies to your organization and download the application. There are numerous sites on the Internet, which announce grant application deadlines and additional information.
Each site is specific to the funder, whether it be federal, state, or private foundation funding. Become familiar with which funders would support your area, and then research those sites. Internet search engines are very helpful in narrowing down the field of potential funders.
Additional information on available grants in usually provided in professional journals or magazines, or in by subscription periodicals.