Construction of the flak 38 begins with the housing about which the barrels pivot. For the most part, this fits together as a basic box assembly. From there the side plates where the guns themselves are mounted get attached and these aren't glued so that the final assembly pivots. A screwdriver is used to hold the gun sight linkage in place and also pivot, however, I opted to just glue this all in place at a slight upwards angle.
Assembly then moves to the baseplate where the entire thing is attached and is able to spin around like the real gun, shields are then added to the front along with some additional magazines and the operator's chairs.
Also included in the box was the trailer that the gun was attached to be able to move it from site to site. This was a rather quick assembly to do with basically the wheels and basic suspension added and called it a day. Since I've modeled the gun in the firing position the trailer can be staged nearby.