Sequencer (shots and MasterSequence editing)

Hi,

I have question about how to edit/trim shots in sequencer.
How do you make a shot shorter is this done in the (Shot) it self, or do you do this
in the Master Sequence?

For eg. If you make a shot shorter lets say from frame 0 to 90 instead (100) so that’s
10 frames less. How does this work in the MasterSequence is the shot then also shorter?
Can you also adjust this in the MasterSeq?