What does the phrase “weigh down” mean here?

Question

Here is a sentence from an adventure game:

In the game, you use your enemy's corpse as bridges and to weigh down pressure plates, providing cover from spears-firing traps – sometimes for yourself, and sometimes for blocks need to be kept intact so you can use them as stepping stones.

I am not sure about the function of pressure plates here. How can they provide cover to the player from traps by being weighed down?

Answer 1

To "weigh [something] down" means to put a weight on top of it to push it down.

In your game, if a spear is triggered by the weight being applied to a "pressure plate" on the floor, then having a weight on it continuously could prevent a spear being triggered when the player walks across it.