Imagine that we have 10 Labels from up to down in a Form, that each of them contains a number.
How can I sort these Labels?, so that the greatest number go to the top of Labels and the smallest one go to the end?

Do you want to programmatically switch out their captions or move each label on the form?

You could use a listbox to do this, but assuming you have reason to not do this,
Create a label array

Label[] labels = {label1, label2 etc}
for(int x = 0; i < labels.Count(); x++)
{
    var changes = false;
    for (int i = 0; i < labels.Count() - 1 - x; i++)
    {
        if (Int.Parse(labels[i].Text) > Int.Parse(labels[i + 1].Text)
        {
            var x = labels[i].Top;
            labels[i].Top = label[i + 1].Top;
            labels[i + 1].Top = x;
            changes = true;
        }
    }
    if (changes == false)
        break;
}

I didn't write this in the compiler, so some parts may be wrong. Check it over. This is the bubble sort I have done in maths. The reason x is taken away each time is because the highest number sinks to the top every pass, so you don't need to compare it. The - 1 is because you cannot compare the last on its own.