Afterwards / Beforehand

After: Después de... http://www.wordreference.com/es/translation.asp?tranword=after
Afterwards: Después de esto http://www.wordreference.com/es/translation.asp?tranword=afterwards

Before: Antes de... http://www.wordreference.com/es/translation.asp?tranword=before
Beforehand: Antes de esto http://www.wordreference.com/es/translation.asp?tranword=beforehand

Rules:

1- After & Before: are followed by a noun or verb.
2- Afterwards & Beforehand: replaces a noun or verb.
3- Earlier & Later: refer to time.
4- Before & After: refer to events.
5- After: después de
6- Afterwards: después de esto
7- Before: antes de
8- Beforehand: antes de esto

I went there and afterwards I went straight back home.
After I went there I went straight back home.

Before I came here I had had lunch on the tube.
I came here at 15:45, beforehand I had had lunch on the tube.
!!!! Beforehand with Past Perfect