How do I read the output of a shaft encoder to control the angle of a motor on myRio

Hello guys,

I am new to control and I have a project to control the position (angle) of a DC motor using a shaft encoder.(600 pulses) 

I  am using myRio and labview and was able to get a digital output from my encoder.

I need to design a PID controller to control my motor so most probably PWM is used for velocity.

What to do with theses readings, how to transform into angle position?

and how can i use the PID option on myRio.

Any help is appreciated and thank you for your time