Detect if player is in area

You could create a region 3 and repeat check if the player was in it

local Region = Region3.new(minVector, maxVector)
local Character = plr.Character

repeat
	wait(5)--change at will
	local Parts = Workspace:FindPartsInRegion3WithWhitelist(Region, {Character.PrimaryPart})
	if #Parts > 0 then--Thing is there
		--do stuff
	end
until false

This probably isn’t the best way but it is the easiest way I could think of