From what I recall from my father

4 very large ginger peeled and coarsely grated
1 stick cinnamon
1 cup sugar

One of those glass apple juice jugs or some large glass vessel with lid

Mix all together and place in jar in a dark warm area of the house.
Let it sit for a couple of days.

Shorter time if it is a very sunny or warm area. Definitely no more than 4 days.

Then you can add more sugar to taste and dilute if needed. My dad also added freshly grated nutmeg.

Some people like to add lime to the brewing proces.