The mob works by spawning near the player and waits for the player to find them. Once the player finds the mob they can do one of two things

1: Look at the mob to scare it off (the mob will teleport away)

2: Get closer to the mob without looking at it which will aggravate it and make it attack the player (after about a minute or so of them chasing the player if they cannot catch the player they will teleport away) (The mob will also break the doors of a player's build if the player tries to lock the mob outside when it's aggravated unless the player's build uses iron doors)

(Version 1.0.4 and up: The Lurker will teleport away once it has killed a player and will have a chance to walk towards the player and stop at a certain distance away)

(Version 1.1.9 and up: If the Lurker gets trapped in a boat/minecart he will immediately exit the boat/minecart)

(Version 1.2.2 and up: The Lurker has a small chance to get angry if the player looks at the Lurker and the Lurker can be invisible and follow the player)

(Version 1.2.10 and up: The Lurker has variants. The "Faker", which will spawn on insanity stage 6, will jumpscare the player and increase their insanity stage by +1. The "Hider" will hide within the ground when looked at, and if the player gets too close, it will teleport away and leave behind a Void Gateway. The "Shadow" will stalk the player in dark places like caves and can jumpscare the player. The "Unprovoked" variant will become aggressive for unknown reasons. The "Shapeshifter" will appear in villages and can deceive the player into trading with them, and if the player is tricked into trying to trade, he will proceed to attack the player, although if the player figures out who the shapeshifter is and hits him, he will transform back into the Lurker and run away. The "Neutral/Runaway" will watch the player, and if the player looks at it or gets close, it will either run away or walk towards the player.

The Void Gateway is a portal that the Lurker can leave behind in random spots around the world. Upon interacting with the gateway, the player will either be jumpscared or rewarded by reverting an insanity stage back by 1.

When a "Neutral/Runaway" spawns, it will start the insanity timer of the player closest. If a player kills the "Neutral/Runaway", then the insanity timer will stop, so the player is no longer progressing insanity stages.

When insanity reaches stage 7, the "Aggressive" Lurker will spawn and chase the player down. This Lurker has different traits from the normal ones, as he can duck and crawl into spaces to reach the player. He can also break glass and doors, and if underground, tunnel towards the player if there is space for it. All Lurkers who walk or run will now be able to climb to get to the player.)

(Version 2.0.3 and up: Any Lurker variant can be attacked directly by the player if lurker_invulnerable is set to false when this is set to false the player's shield will go on cooldown for 2.5 seconds when attacked by the Lurker so the player can't shield spam to kill the Lurker)

(Version 2.2.9 and up: When the player sleeps through the night insanity will stop progressing until the next neutral Lurker spawns)

(Version 2.5.0 and up: The player can eat food to reduce or increase insanity the player can also fish to reduce insanity The Neutral/Runaway Lurker will stop walking towards the player when close enough and will run away when the player gets too close)

(Version 2.5.8 and up: The player will get "Amnesia" on insanity stage 6 and the Amnesia will despawn mobs if you are close to them and looking away)

(Version 2.8.2 and up: The Void Hands are a variant of the Void Gateway, and when the player gets too close to it, it will reveal itself to the player and will then start to chase the player. The Void Hands can open doors, and once they have low enough HP, they will teleport away and jumpscare the player)

(Version 2.8.7 and up: The invisible entities have a low chance of spawning and when around the player can do certain actions which includes playing a static like jumpscare, playing cave sounds to trick the player into thinking they're being watched, following the player, watching the player, and playing Lurker running sounds as a sort of fake out.)

(Version 2.9.8 and up: The "Creep" will watch the player, but if the player attacks or goes really close to it, then it will attack the player, and if the player looks at it, then it will teleport near the player instead of teleporting away. The "Unprovoked",  "Stare",  and Nether variants of the Lurker can be stunned when attacked but will have a stun cooldown period where the player cannot attack them. The "Phantom Head," if looked at, will slowly float towards the player, and if close, will force the player to look at it as it gets closer and closer. The damage of the Lurker variants that are able to attack the player scales with the player's armor, so they are never safe, even when overpowered. The Shapeshifter Pig and Cow will attack the player if the player tries to kill them for food. The Lurker will kill animals if the player is not near. The "Unprovoked" won't always disappear when looked at. The Lurker will swim somewhat faster if the player is in a boat.)

To use the config, you have to go into your Minecraft game directory, then go into the "config" folder and it should be there. You can edit the config with Notepad, Notepad++, or any code editor you may have installed.

Or, alternatively, you can install the Configured mod and access the config menu by finding the mod in the "mods" tab in the pause menu and opening the config that way