Adjusting the Potentiometer into Acquired Value
What's the problem?

You turn the potentiometer while observing the collector current until the current equals the defined values 0.2, 0.4, 0.6...

You'll find that as you turn the potentiometer one way the current increases and goes down when you turn it the other, so just get the desired current then don't touch it while you make the voltage measurement. Then do the next setting/

When you have adjusted the collector current to each of those values you measure Vbe and Vce with a volt meter.