Spinodal and Isotherms graph on P-V diagram

[ReuvenD10]

Hey guys,

During my work I have to show on a P-V diagram certain points on the spinodal for water.

How do I draw the spinodel and isothermal lines on a diagram (for example in Excel)? Is it something that I need to calculate? I'm lost on this, I did not find anything relevant on the internet.

Thanks for the help.