Never had this to happen before. You are going to have to drain coolant, remove hoses from radiator and pump and remove fan blade. Loosen the belts and remove all the bolts holding the pump to the block and lightly pry the pump from the block.(It may not come off easy)
Clean the surface of the block where the water pump seals, use sealant cement on both surfaces and fit the gasket onto the pump, put a couple of bolts through the bolt holes to hold the gasket in place while you fit the pump to the block, tighten all bolts and reinstall belts. (At this point you may want to purchase new hoses and belts depending how old they are) Install fan and shroud. (How bad is shroud tore up?) Install radiator and hoses. Fill with coolant, start vehicle and check for leaks.
Hope I didn't leave anything out, and you can always purchase and Haynes or Chilton manuals from local part stores. The whole process doesn't take very long.