You now owe this guy RM200 Siong90 for his help.

its best if u forget about just training ur arms and chest only.
its gonna make u look weird: big arms, big chest, small chicken legs, flat baby back. besides, it'll introduce muscle imbalance and possibly lead to injuries.
focus on training ur whole body, not just the "show muscles"

unless the dumbbells are adjustable and u have a good amount of weight plates, its still best to find a decent gym.

for starters, try looking at stronglifts.com
read read read and read.

set a goal, train with compound exercises, eat to support ur muscle growth, get enough rest.