The Isothermic process is where the temperature is kept constant while both volume and pressure are increased/decreased. T= PV/nR. For this, I set n = 1 mole, Pressure is in KPa, T is in kelvins, V is in M^3, and R = 8.31 KPa* m^3/mol* K. As the temperature increases, the gas expands, pushing the weight further and further up.
As stated previously, work done can be calculated by getting the area under the the points. I will not address Q here, however.
Click on the flash window. If you hold down the up/down key, the volume will rapidly change.