I appreciate your lack of chemistry knowledge, but it makes it difficult to come up with an exact mix.
However, you can try this approximation...
Take a water bottle that holds 1 liter of water. Fill it with water. Add to that 1/8 teaspoon of Miracle-Mineral-Supplement . Also add 1/32 to 1/16 teaspoon of your citric acid . Let it sit overnight and then check it out in the morning.
You may find it very easy to drink. You can then enjoy your juice at a separate time.