Break out your Jack LaLanne
power juicer and juice approximately 1/2 lbs of ginger root. You should get around 150 mL (more than half a cup) of juice. It is also possible to use a ginger grater to collect the ginger juice; it will simply take more time and effort. Here's a discussion.
Next, juice enough apples to make 1 liter of apple juice; probably around 8 large apples. Store-bought apple cider will also suffice for this, but you've got the juicer out, why not use it?