It's a fantasy role-playing game.

DM: You are Percival de Rolo, a human gunslinger . You are the member of the famous group of adventurers. Previously, The party finally decides on a two-pronged plan. Vax and Scanlan will sneak in to kill the illithid, while the rest of the party creates a distraction and try to blind them with light.
DM: Plus your tinker's kit proficiency. It's down underneath your skills. Proficiency, at the very bottom left.
Player: Yeah, I don't have a number for that.
DM: You can add your proficiency modifier to your intelligence check. Add your intelligence modifier plus four.
Player: Ah, thank you. 17.
DM: All right, and so what are you trying to accomplish with this arrow again?
Player: I was just trying to make an entanglement arrow. It's a trapper's arrow.
DM: Okay. You manage to work out what seems like a tanglefoot bag-type detonation, where if an arrow were fired, it would be a grapple check against the individual, probably give them penalties until they're able to break free of the grapple. So yeah, success on that one.
