Start by squeezing out the juice of your fresh lemons using a lemon squeezer.
Next, start to puree the blueberries and blackberries and pour the contents into a strainer when done.
In a sauce pan, add the sugar and a 1/2 cup of water heating in on medium heat until the sugar dissolves (about 5 minutes or so). This will be the base of your lemonade.
Remove it from the heat.
Stir in the other 3 cups of cold water and the freshly squeezed lemon juice.