Let us say that you need a number of motors equal to the number of degree of freedom or joints as our brother said above, But you also seem to need to read a bit more and use google and youtube.
Components like: motors, gears, belts, links.
Tools: Actuator selection, SolidWorks for 3D model building, hmm and Matlab Simulink for controller design.
Search about robot arm, actuator selection, dynamics, kinematics, use grab-cad to get some 3D models and familiarize with, go to Wikipedia and try knowing more about electronics and get something built with your hands.
And please Read
You are in society of robots you can know all what you need from the valuable topics here (not the forum)
i mean http://www.societyofrobots.com