If you are going to make a tea made of both, you may boil the roots and then add the leaves to steep when you remove it from heat. One would typically make such a tea in 1-2 quarts of water. You will know if it has spoiled because it will begin to stink. Sometimes you can get away with a day and a half, and the cooler it remains the longer it will keep. As to how much herb to use in your tea, that is a matter of which you will have to educate yourself.
Different herbs have different effects.
Some will make you quite sick if you try to take a large dose of them, such as Cascara bark, or Poke root. But most you can take several tablespoons in a batch of tea, and it will only increase the healing effects. Because this method of taking herbs is not as convenient as popping few pills, some are adverse to attempting it. But while it does take more effort, it also has the benefits already described For those who have tried herbal remedies with little effect, insufficient dosage is a possible cause. But for those who must at all cost have convenience, there are herbal tinctures.