Biophysical Processor issues using ENVI hdr data

Last question about the graph - Builder.
An ideas about how to put a mask cloud to the final product so I get null values?
Thanks again for your time!

you can use the Land/Sea mask operator and use a vector as a mask or simply apply the Band Maths to exclude values based on a logical expression. Can you describe which pixels you want to mask?

Only the pixels that have clouds (NaN value). Finally, I would like a product with biophysical indices + NDVI and mask out all the clouds (plus shadows). I think I must use the scl masks but at what phase in the graph model and how?
Thanks

Please have a look here - I think this discusses the same approach: Image Classification