Good day to you all!

I am in an urgent need of writing a Solicitation letter. This is my first time writing one so I have no idea what to put in it. I am part of an orchestra and I am in need of a Cello. I need financial assistance in aquiring one. Most people suggested to write a solicitation letter but the problem is, I have no idea what to put in it. Could anyone show me a sample? I also tried to search for different samples of solicitation letters but did not find what I wanted to find. Any form of help will be greatly appreciated!

Thanks everyone!