How long does it take to set up a Hunting Trap? How does it work?

Question

Can you affix the heavy chain to an immobile object when you use your action to set a Hunting Trap (PHB p. 152), or is it just the opening of the teeth that takes an action? The text says:

When you use your action to set it, this trap forms a saw-toothed steel ring that snaps shut when a creature steps on a pressure plate in the center. The trap is affixed by a heavy chain to an immobile object, such as a tree or a spike driven into the ground.

and

A creature that steps on the plate must succeed on a DC 13 Dexterity saving throw or take 1d4 piercing damage and stop moving. Thereafter, until the creature breaks free of the trap, its movement is limited by the length of the chain (typically 3 feet long).

If it's not all done in an action, then can you use the trap without the chain? How long does it take to affix the chain? Does this include driving the spike into the ground?

Answer 1

The entire process of setting takes one action

As written, there are no additional actions needed to set the trap: the description states

When you use your action to set it,

all the rest is a description of the effect of the set trap. This includes limiting a creature that triggers it to the length of the chain, so by setting the trap you also affix the chain. How you narrate this is up to you.

In case you are wondering how that would be possible within a single action (which is just a part of a six second round, you also can move, have a free object interaction, and possibly take a bonus action and a reaction within those six seconds): this is not the only instance where what you can achieve within just six seconds appears entirely unrealistic. For example, the free object interactions list (p. 190 PHB) includes "withdraw a potion from your backpack", and if your backpack is on your back and the potion somewhere down in its bowels, that would seem awfully difficult to do in such a short time.

Always remember that the rules of 5e give the DM liberty to adjudicate or overrule the rules, when a rule or interaction appears nonsensical to them (p. 4 DMG):

The D&D rules help you and the other players have a good time, but the rules aren't in charge. You're the DM, and you are in charge of the game.