How to build massive arms

First of all i need little information about you age, height and weight. And do you work out at home?? If yes then what equipment do you have ?

Any way 12 is very small for bicep of a 5' 8" and above. So i give a little idea how to build arms at home with dumbbells only.

Biceps:
Alternate dumbbell curls 3 sets 8-10 rep
Concentration curls 3 sets 8-10 rep
Hammer curls 2 sets 8-10 rep

Triceps:
Close hand push ups 3 sets 8-10 rep
Dumbbell tricep extension 3 sets 8-10 rep
Bench dips 3 sets 8-10 rep
To grip strength u require both but forearms more than arms, so 4 that home exercises r ---
FOREARM--
1) sit on a stool, than fill water in bucket,after that sit on stool with arms resting on ur laps & do wrist flexion--this is to buils wrist flexors.
2) in above position move wrist in opp.direction--this is to build extencers( u will be able to carry less weight as comparted to flexors).
3) using some heavy book or something , do hammer curl ( plz check NRT 4 hammer curl-its 4 lateral arm).

BICEPS--
1) using bucket half full plz do arm flexion.

TRICEPS----
1) using heavy book or something plz do side posterir curl....

PLZ do it for 15 days & tell me later....
he hard truth is you'll never build MASSIVE arms without years of heavy weight training. You CAN greatly improve your arms just by doing pushups, chair dips and chinups at home.

Your forearms start with the grip. All you need to make a good start on larger, stronger forearms is a simple rubber ball, one of those foam grippers or even a spring loaded grip exerciser. You can work that hard - until your forearms fairly scream - once a day, every day.