How can I use two 8lb dumbells to build muscle for my forearms?

As with the use of all weights it's all about repetition, if you keep repeating the same exercise with weights then eventually you will get a result, however if you want a reasonably overall shaped body then you will need to devise an exercise regime where the rest of your body is exercised as well, it's no good just sticking to your forearms if all you end up with is massive forearms where you can crack Brazil nuts with your elbow joint.

Suggest you go to your local gym and ask for some advice explaining that you don't have the money for gym fee's but would like to improve your overall body shape.

Build Ripped Muscle Fast

the forearm muscle mass are effortless with a dumbell in each and each hand status up of direction you twist your wrist intowards your body. this works the forearm also do a bicep curl yet carry the dumbell oposite of a bicep curl so as that your hand is on properly. as for the legs operating will lead them to better besides the indisputable fact that the superb way may be with kit or weights to do squat with.

Wrist curls, dumbbell lying supination and pronation.

I think you first have to be able to pick them up!