Why does it appear really far away when it should appear super close?

local DefinitelyPlane = workspace:FindFirstChild("1")
local PlaneName = 1
local Plane = workspace:FindFirstChild(PlaneName)
local PositionXX = 103.4
local PlayerQuantity = 0
local PositionBr = PositionXX, 5.8, -919.8

game.Players.PlayerAdded:Connect(function(Player)
	PlaneName = PlaneName + 1
    PlayerQuantity = PlayerQuantity + 1
    PositionXX = PositionXX - 15
    local RPlane = Plane:Clone() 
    RPlane.Parent = workspace --see, like this
    RPlane.Name = PlaneName
    RPlane:MoveTo(Vector3.new(PositionBr))
end)

local a = 1,2,3

a is not equal to all three numbers, it is equal to 1.

local a = Vector3.new(1,2,3)

Now, a is equal to a Vector3 of all the numbers.

local PositionBr = PositionXX, 5.8, -919.8

As previously mentioned, PositionBr is now only equal to PositionXX

Due to the incorrect Vector3 construction, it defaults to 0,0,0

Relevant devforum post.