The belt that drive the cutting blades on my mtd rideon mower bought June 2000 has come off I need a diagram to show how to replace it correctly

Hi,
Have no clue what those numbers mean. An MTD model number is 11 spaces long; numbers, letters or hyphens.The is a link below my name in my sig to OPE by Crigby that shows decks for MTD.
Peace,
Clarke