Alright this is an arm build I used in a previous MOC topic of mine and its kinda easy to build. It's better used for bigger MOCs but uh.. I don't really care on what you do with them XD.
I'm just gonna do one arm cause they're just the same build and I'm kinda lazy.
Ya need these.
(You squeeze them together and make sure the axle is sticking out on both sides)
(Comnect the part I made earlier like this)
(Then flip it over and add this piece)
(Now bend it at a 90 degree angle and add those 2 pins)
(Now add this technic piece and flip it over so that the technic parts are pointing to your right)
(Now push that part in and do the same steps to make another arm)
(Connect the other arm on)
(Then add a CCBS torso if you want, it's optional. Then just add some armour)
And you done son!