When a young Sovereign first orders their first Farm, they are using the Civic construction queue. The construction cost is paid and the timer starts. This construction project can be cancelled, but the Sovereign will lose some if not all of the already invested construction materials. While the timer runs, no other buildings can be built or upgraded. When the timer completes, so does the construction. The new Farm is available and another construction project can be started. Upgrading a building uses the same process, with the building available at it's new level with the construction timer is complete. Queuing allows Sovereigns and Ministers to line up a few buildings per district they'd like to build one right after the other. The number of 'waiting' slots in each queue depends on the rank of the District, the maximum slots per queue being 7.
Civic Construction Queues
The Sovereign and Ministers within their overseen district use the Civic construction queues. These are buildings the government wants built. For the most part, just having the queues will be handy enough for most managing members of government, but shenanigans are more than allowed for players who want to make use of both queues at a time. Since there is no competition for civic control over a district, Civic queues don't need to account for contradicting orders. They methodically build one building after the next at the will of the Sovereign or Minister controlling the district.
Private Construction Queues
The Private construction queue provides a way for private property owning citizens to make sure their buildings get built without interrupting government management. On the other hand, the queue can still only build one building at a time. Construction is a fairly placid concept when there's only one influence trying controlling what is constructed. What happens when there are multiple private owners in a district who all want to their building built or upgraded first? For this, the players are welcome to bid on the highest slot, or just to have a slot at all. When a player bids, their payment is taken by the queue, usually until their construction project is complete. Whoever is the current highest bidder gets the first queue slot, with the second in second and so on. It is possible to raise your bid after your initial offer in order to keep yourself in the running. If there are too many bids higher than yours and your building is bumped from the queue, your bid price will be returned to your inventory.
Populace Construction Queue
About half of the Economy options provide a small percentage of total building lots to the NPC populace. When they both own lots and have the correct material wealth, the Populace will start their own construction projects. The populace have their own separate construction queues and will never interfere with the player queues, nor will players be able to use the populace queue.