Best response to ruy lopez

3...a6 (possibly) 

Where is blueletterbeard or whatever his name was ?

I was hoping more for something like 3...g5....but perhaps we should move f6 first.

engine says its a3 but i go for the berlin

Possibly helpful:

First Steps: 1 e4 e5

https://www.newinchess.com/media/wysiwyg/product_pdf/7790.pdf

Starting Out: Ruy Lopez by John Shaw (2003)
https://web.archive.org/web/20140627024240/http://www.chesscafe.com/text/hansen53.pdf
A Spanish Repertoire for Black by Mihail Marin (2007)
https://web.archive.org/web/20140626195205/http://www.chesscafe.com/text/hansen102.pdf
The Berlin Defence by Igor Lysyj & Roman Ovetchkin (2012)
https://web.archive.org/web/20140627104938/http://www.chesscafe.com/text/hansen159.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/7076.pdf
The Ruy Lopez: A Guide for Black by Sverre Johnsen and Leif Johannessen (2007)
https://web.archive.org/web/20140627023224/http://www.chesscafe.com/text/hansen94.pdf
Bologan's Ruy Lopez for Black by Victor Bologan (2015)
http://www.sjakkbutikken.no/produkter/bologans-ruy-lopez-for-black/
https://www.newinchess.com/media/wysiwyg/product_pdf/9016.pdf
Play 1 e4 e5! by Nigel Davies (2006)
https://web.archive.org/web/20140626201436/http://www.chesscafe.com/text/hansen80.pdf
https://web.archive.org/web/20140627083715/http://www.chesscafe.com/text/hansen98.pdf
The Berlin Wall by John Cox (2008)
https://web.archive.org/web/20140627050257/http://www.chesscafe.com/text/hansen115.pdf
Attacking the Spanish by Sabino Brunello (2009)
https://web.archive.org/web/20140627105306/http://www.chesscafe.com/text/hansen124.pdf
http://www.qualitychess.co.uk/ebooks/Attacking_the_Spanish_excerpt.pdf
The Ruy Lopez Revisited by Ivan Sokolov (2009)
http://dev.jeremysilman.com/shop/pc/Ruy-Lopez-Revisited-The-p3765.htm
https://www.newinchess.com/media/wysiwyg/product_pdf/931.pdf
Fighting the Ruy Lopez by Milos Pavlovic (2009)
https://web.archive.org/web/20140627105306/http://www.chesscafe.com/text/hansen124.pdf
Slay the Spanish by Timothy Taylor (2011)
https://web.archive.org/web/20140627040230/http://www.chesscafe.com/text/hansen146.pdf
The Kaufman Repertoire for Black & White by Larry Kaufman (2012)
https://web.archive.org/web/20140626221508/http://www.chesscafe.com/text/hansen162.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/955.pdf
Grandmaster Repertoire 13 – The Open Spanish by V. Mikhalevski (2013)
http://reviews.dailychess.org/grandmaster-repertoire-13-the-open-spanish-qualitychess-by-v-mikhalevski/
https://www.newinchess.com/media/wysiwyg/product_pdf/7234.pdf
Anti-Spanish. The Cozio Defence by Alexey Dreev (2014)
Playing 1.e4 e5 - A Classical Repertoire by Nikolaos Ntirlis (2016)
https://www.newinchess.com/media/wysiwyg/product_pdf/7572.pdf
http://www.qualitychess.co.uk/ebooks/Playing1e4e5-excerpt.pdf
The Spanish Main Road by Evgeny Solozhenkin (2016)
https://www.newinchess.com/media/wysiwyg/product_pdf/7595.pdf
The Zaitsev System by Alexey Kuzmin
https://www.newinchess.com/media/wysiwyg/product_pdf/9036.pdf

The Schliemann Defence: Move by Move

https://www.newinchess.com/media/wysiwyg/product_pdf/7797.pdf

ok and then?

This is just the beginning of a myriad of variations...

on move 3, u have choice : a6, d6, Bc5, Nge7, f5, Nf6, g6.

Then u have other choices on move 4 especially after 3...a6 4.Ba4 : we could enumerate about 20 playable variations for black, and maybe more...