Need help with building an outdoor fireplace!?

I am attempting to build an outdoor fireplace. I don't know much about masonry, and need some advice. I am not sure how to measure for my firebox and flue. I've got a 5 x 8 foundation poured, I've got 50 cinder blocks and 75 fire bricks. I plan to make it around 10ft high with a 16inch ledge from the bottom. I need some advice! Anyone with any experience in this area? I'd really appreciate it!