ServerScriptService.Script:3: attempt to call field 'Name' (a string value) ?

game.Players.PlayerAdded:Connect(function(plr) 
    local leaderstats = Instance.new("Folder")
    leaderstats.Name = "leaderstats" 
    leaderstats.Parent = plr


    local val = Instance.new("IntValue")
    val.Name = "Points"
    val.Value = 0
    val.Parent = leaderstats

    local val = Instance.new("IntValue")
    val.Name = "Wins"
    val.Value = 0
    val.Parent = leaderstats
end)

Why were you doing this leaderstats.Name("leaderstats"), .Name is a property that you need to set to a string value, string values are a group of characters and words inside of these " "

"this is a string"
"pizza 25"
"cool"

Doing leaderstats.Name("leaderstats") doesn't make any sense, well it does, if .Name was a function, and "leaderstats" will act up like a paramater to it, but not in your caset, Name is a property, this the way of setting properties.

leaderstats.Name = "leaderstats"

Remember that = (this is called an operator) is used to set properties, or variables to something, something.function() and this format is always acting up like a function