you just need a glass bottle (pressure lids are good), abt. 5 g sugar per 100 ml, some cleaned tree needles. everything into the bottle, filled with water to around 80-90%, wait for 3 to 5 days, let it sit in the sunlight at a warm spot

alternatively you can use honey instead of sugar, or add some ginger, rosemary, lavender etc for better taste

really easy and gets fizzy, tastes good, but you might have to try a few times before you get a good mix