Centennial Blonde is going to be first all grain. If I understand correctly I need about 6.5 gal of water for 5 gal batch. How much water for should mash, and I guess an hour and then sparge the rest of the water thru?
Head over to John Palmers website: HowToBrew.com, read through, you will probably buy the book after, most brewers have this one.
To answer the question we need to know what type of equipment you have.
Typically I mash 60-90 minutes with 2.5-3.25 gal of water for an average brew, I batch sparge with 3.25-3.75 to get 6.25 or 6.5 gal boil. Big factors are your crush, amount of grains, your equipment.