Where can I find a start up file for the Apple 512k to burn to a floppy?

I have a 1.44mb floppy and people said you need to burn it to that and than transfer it to a 800kb floppy on a mac. Can someone give me a link with the start up file and direction on how to burn it to a floppy. I have a Apple 512k but don't have the startup floppy. I have an external floppy drive that hooks up to it that read 800k. Thanks!