The vacuum brewer or a siphon consists of a lower bowl used as a water reservoir, a filter, a brewing upper bowl with a long vertical stem and a burner. Assisted by the heat from the burner, the hot water shoots up through the coffee grounds, agitating grounds during contact time and creating vacuum in the lower bowl. Once the burner heat is turned off, the vacuum created in the lower bowl draws the brew from the brewing bowl through the filter back into the lower bowl. Once all coffee is filtered, the top half of the brewer is removed and the coffee is served. Use 6 g of coffee per every 100 ml of water - you may upsize your water amount slightly to allow for some retention of water in the grounds at the end of brewing. Target brewing times of 3.5 to 5 minutes.
Tip: Not all vacuum brewers are born equal. Some of the oldest designs, like Cona, use glass filtering system - you will need a finer grind for them. More recent designs (Hario and the like) use cloth or paper filter - this works well with a coarser grind suitable for manual drip method. If you are using a Cona brewer and your filtering time is too long, grind your coffee finer.