Hello,
the suggested INCAR in the tutorial sets LMODELHF, which automatically forces LHFCALC=T.
Please read the corresponding wiki page for more details.
The value for the screening length HFSCREEN has been empirically found.
For other systems, other values are more appropriate. This is discussed in more detail in the supplementary information of Scientific Reports volume 6, 28618. This paper is also cited on the wiki page of LMODELHF.