That’s thousands of tutorials that would need to be ‘updated’ (read re-made) and 2.80 is different from 2.81 is different from 2.82 is different from 2.83….
This specific tutorial is mostly a bunch of Voronoi Textures, so maybe it helps if you compare this:

to this:

Use the Distance output from the Voronoi. Use a Vector > Displacement Node instead of a Math Node. What used to be called True is now in the Material Settings under Displacement and is now called ‘Displacement’ (what used to be called ‘Both’ is now ‘Displacement and Bump’).
The principles in all these Shader Forge lessons haven’t changed.
I think that covers most of the differences, but if you get stuck just ask;)