My daughter bought me this which is very good.

 
Also you can download guitar electronics for musicians here
 
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjmx8uNl_vrAhXTfMAKHVsYCYwQFjABegQINhAB&url=http%3A%2F%2Fmilas.spb.ru%2F~kmg%2Ffiles%2Fliterature%2FGuitar_Electronics_for_Musicians_-_Donald_Brosnac.pdf&usg=AOvVaw0ewY1IuRv7DYL3kIxbRcQL