How to select a NEW random number?

Hey, try this and see if it works fine :)

local maps = game.ReplicatedStorage.Maps:GetChildren()

for i = 1, 3, 1 do
    script["Map"..i].Value = math.random(1, #maps)
end

Additionally, if you want the maps that have been chosen already to not appear again, you will need to use tables.

here's how I'd do it.

local maps = game.ReplicatedStorage.Maps:GetChildren()


for i = 1, 3, 1 do
    map = math.random(1,#maps)
    script["Map"..i].Value = map
    table.remove(maps, map)
end

This will remove the map that has already been chosen so the next one that gets selected will not be the same.

That my friend is not how the Random class works. Let me explain.

The Random class allows you to create a new random object and you can also specify an optional seed. Such that: rand Random.new([string | float Seed]) using this newly created random object you have the choice of 2 functions one is: int rand:NextInteger(int Min, int Max) which returns a random integer between min and max. The other function you have is: float rand:NextNumber([float Min = 0, float Max = 1]) this returns a random float between min and max which will be 0 to 1 if not specified. The random object also has another function rand rand:Clone() which returns a new random object with the same seed and internal iteration.

So here is how you would use it:

local rand = Random.new()

local randomInteger = rand:NextInteger(0, 10)

print(randomInteger) -- Output: 1, 2, ... 10

And I know this isn't a request site, but for your case you would do this:

local maps = game.ReplicatedStorage.Maps:GetChildren()
local rand = Random.new()

-- You also need to index the "maps" table in order to get the objects, otherwise you would just get a number between 1 and the number of maps
local map1 = maps[rand:NextInteger(1, #maps)]
local map2 = maps[rand:NextInteger(1, #maps)]
local map3 = maps[rand:NextInteger(1, #maps)]
script.Map1.Value = map1.Name
script.Map2.Value = map2.Name
script.Map3.Value = map3.Name

The above code can be simplified to:

local maps = game.ReplicatedStorage.Maps:GetChildren()
local rand = Random.new()

for i = 1, 3 do
    local map = maps[rand:NextInteger(1, #maps)]
    local value = script:FindFirstChild("Map"..i)
    if value then
        value.Value = map.Name
    end
end

I hope this helps!