The story you must tell is the story they want to hear.
It is not a general story about your foundations and overall purposes. It is a story about how you know that you can achieve the funders’ specific purposes with the funds you are requesting.
Don’t waste space telling them details about other work you do unless it is clearly valuable. Thinking of it as a story helps you to ask yourself whether it draws in the reader, whether it makes logical progression, whether it makes a satisfying conclusion.
The more specific you are in fundraising the more successful you will be. The more general you are the more you will fail. Be particularly specific about whose needs you are responding to – it shows that you understand your community and can serve them well (e.g. not all children, people with disabilities, dance pupils, gardeners have the same accessibility issues or goals).