The "Brute 828" is a marketing name not a factory identifier. Without a specific factory model number off the tag on the back base of the machine below the handlebars it gets tough to find a manual.
You can go to the site below and walk through various models to find one like yours. There are mostly parts breakdowns there. For an owners you can use just about any manual.
http://www.partsandservice.com/html/Murray/st/