How Do I put the players in first person when they reach a specific area?

I haz no idea, mate..

It's actually quite simple, though it may not look it.

This script will only work if you have a block the player will touch when entering the area.

FP = false

function FirstPerson(hit)
	if hit.Parent:FindFirstChild("Humanoid") ~= nil then
		Person = hit.Parent.Humanoid
		if game.Players[Person.Parent.Name] ~= nil then
			if FP == false then
				FP = true
				game.Players[Person.Parent.Name].CameraMode = "LockFirstPerson"
			else
				FP = false
				game.Players[Person.Parent.Name].CameraMode = "Classic"
			end
		end
	end
end

script.Parent.Touched:connect(FirstPerson)

Put that in whatever block is detecting the player, and you're golden.