how to make a good arm muscle ?

saynow111

i can make push up and my body weight is over 100 kgs

i have dumbells 5 kg , 8 Kgs ,10 kgs

2 dumbells from each weight

any good exercises i can make to have strong arm muscles

how many rest days should i have per week ?

nowdays i barely can make 20 push up

i cant even reach the 20 push up

i can do 15 push ups may be

i never focused and did arm muscle exercises

i even bought the dumbells and didnt use them alot

thank you