I would like to know the proper method of saving my geraniums over the winter so that I can replant them in the spring.

Hopefully the sun-dried geraniums were not thrown out but given a cool area where they can spend the winter untouched by human hands, unlit from any source of light, dry as the sun did them.
AT the time you probably did water them to moisturize the roots--that's alright...but eventually they are allowed to dry out and not be bothered by any water whatsoever until they are brought out again in February to rewnew themselves.

AS long as you give them a place where they are not touched by cold frost or heat. Frost harms the leaves and heat initiates growth...as does light. We don't want them to grow at this time.
They need no water---no water whatsoever..let them sleep the winter away, dry, dark, and cool.

See other messages describing the method to renew geraniums
by cutting them back, given fresh potting soil in a clean pot and given a sunny window where they will grow again, as good, as big as ever.