Apt-Target release,how to set?

if you want to spin unstable tool, you should do.. 

• edit /etc/apt/conf.d/sources.list

 

                #### add line unstable #########
deb http://ftp.us.debian.org/debian unstable main contrib non-free

• apt-get update 

Retrieve new lists of packages 
 

reference:

1. https://wiki.debian.org/AptPreferences