how to counter italian game as black?

Maybe consider:
Starting Out: Open Games
https://web.archive.org/web/20140626232452/http://www.chesscafe.com/text/hansen134.pdf
First Steps: 1 e4 e5
https://www.newinchess.com/media/wysiwyg/product_pdf/7790.pdf
"... For beginning players, [Discovering Chess Openings] will offer an opportunity to start out on the right foot and really get a feel for what is happening on the board. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf

Possibly of interest:
How to Beat the Open Games
http://www.gambitbooks.com/pdfs/How_to_Beat_the_Open_Games.pdf
Playing 1.e4 e5 - A Classical Repertoire by Nikolaos Ntirlis (2016)
http://www.qualitychess.co.uk/ebooks/Playing1e4e5-excerpt.pdf
Bologan's Black Weapons in the Open Games (2014)
http://www.jeremysilman.com/shop/pc/Bologans-Black-Weapons-in-the-Open-Games-76p3873.htm
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
Opening Repertoire: The Open Games with Black by Martin Lokander (2015)
https://www.newinchess.com/media/wysiwyg/product_pdf/7546.pdf