how to make a library to control a robot

Dear,
i have material to build a robot, i have four DC motors, one motor controller and one SBC(single board computer), in first i use PC as SBC
i want to make a library in C#, to control the robot
i want to make 5 funtions
one to go forward
one to go backward
one to stop
one to turn left
one to turn right

can you help me?

thanks in advance
best regards