Camo Vest

how do i dye a 100% cotton vest dark blue? it is a digi camo 511 tactical vest that i need to dye.?
I would suggest some Rit Clothes Dye.Available at most dry goods stores or sewing centers,Maybe even find it at Wally World.Possibly the finsh will come out splotchy because the camo pattern will affect the finish.Instructions are on the box(or bottle if you get the liquid.Try using several tablespoons of salt with the dye.It sets the color better so as much won't come out the first time you wash it.Also only wash in cold water.That will cut down on the fading as well.