How to manufacture atom bomb? secret?

Hi this is about atom Bomb manufacturing Technology.

Yes! People of this world not believed that a product can be developed from atom.

But Albert Einstein a great scientists of that time gave a letter to the than President Mr.Theodore Roosevelt in this regard. In this letter he confirmed that an atom Bomb can be produced from an atom. With a Massive strength of scientists and professionals of America produced atom bomb successfully.

so By this, America exposed as a Super power in the world.

Thanks.