Expressing from 36 weeks (GD)

My dr/midwives have asked I start hand expressing from this week onwards to ensure I have colostrum ready to go for bub when he arrives. Apparently it is the best thing to balance his sugar levels if there are issues when he is born and has all sorts of other benefits too.

My question: is there a difference between hand expressing and pumping while still pregnant?

I just can’t figure the whole hand expressing thing out (not that I’ve been persistent and I’m still a few days away from being 36weeks).

Not sure if I just don’t have enough information on how to do it or not 🤷‍♀️

Should I mention first time mum?😂