The charango is often paired with the quena, hence this site, with all the information you could want to get going on either instrument:

http://quenaycharango.blogspot.co.uk/

I found it after buying one of Vannini's quenas in a charity shop:

http://musica-artesanal.blogspot.co.uk/p/blog-page_8867.html

I must sometime try to play that quena along with Galo or his pal Carlos Arredondo (another terrific charango player based in Edinburgh).