Usually, You can connect the Module to a variable rheostats connected in series. Then you can change the resistors values gradually from zero, to represent the short-circuit condition, up to a large value, to represent the open-circuit condition. At each value, you can measure the voltage and the current to draw the I-V curve. Moreover you can calculate the power, P=V*I, to draw the P-V curve as well. It worth to mention that as many values you read, as accurate curves you get..