Most homebrewers carbonate their beer by adding priming sugar at bottling time.
Usual instructions call for about a teaspoon of sugar per bottle.
This terminology is familiar to those who keg. Charts for kegging systems show the gas pressure to apply at each temperature to achieve a particular carbonation level. If this pressure is held for several days, the carbonation reaches its equilibrium value, i.e. the beer will absorb all the CO2 it can at that temperature. In bottle conditioning, the CO2 is produced by the fermentation of an accurate dosing of priming sugar. Just as each style of beer has its own balance of hops and maltiness, so the appropriate level of carbonation varies from beer to beer.