Could you give me a simple translation and explanation of the shmonei Esrei? Is this the Amida (Standing Prayer) and please explain this.

There are many siddurim with an English translation- Art Scroll, Rinat Yisrael and others. Pick the one you find most understandable. The Amida is another name for the Shmone Esrai. It is called "Amida"- standing, because it is said standing. In this sense it is a more inclusive name than "shmone esrai-which means "eighteen". The weekday amida consists of 19 brachot, the original 18 plus one, but the Amida on shabbat and holidays consist of a smaller number of brachot.