Overshoot in vertical metrics

Hi there.

I’m new in Glyphs and I want ask you about the overshoot of the vertical metrics. In a .otf that I import from Fontlab the glyphs has an overshoot on descender but not on ascender.
Can you help me to set this overshoot in both sides?



See 7.2.4 from Glyphs Handbook v.2

You’re right, I did’nt remember the handbook. Thank you! c: