The hobbyist can use several approaches to evaporating their sap. In general, evaporation should be done outside unless only 2 or 3 trees are tapped. Four to six gallons of moisture will be liberated in boiling the production of these two or three trees in a good run. Fromm personal experience with finishing syrup indoors as a obbyist, your house will be more humid than it has ever been. After you start boiling, all the windows will fog in 30 minutes. In an hour, the walls will be wet and you will have some difficulty breathing. So, evaporate outdoors.
For a hobbyist, your arch can be an old stove or an improvised fireplace. Your evaporator can be some big pots or a flat pan (often used as finishing pans). These flat pans can be purchased from a sugaring supply shop of fabricated. Using two evaporator pans/pots is usually faster and results in better syrups. The first pan (the largest) is used to boil the sap to do most of the evaporation. After most of the water is removed, the concentrated sap can be transferred to the smaller pot for "finishing." Large scale producers use an evaporator with "back" flue pans and "front" flat pans for this same purpose. Large evaporators do not usually make sense until a producer has at least 50 taps.