This is the official AT & T LG G3 user manual in English provided from the manufacture.
Download AT & T LG G3 D850 User Manual:
Download LG-D850-ATT_UG_EN_Web_V1.0_070814.pdf
The AT & T LG G3 user manual is also available in Spanish, You can grab it from below direct download Link:
LG-D850-ATT_UG_ES_Web_V1.0_140709-1.pdf
if you have any questions prior to purchasing, please feel free to ask in the comments.
Those who are looking for latest USB drivers for AT&t LG G3 can download it from this page. Do not forget to join LG G3 owners community on Google PLUS to share your tips,questions, answers and reviews.