Hi. This is how it works for us:
Between 10pm and 11pm (depending on when we go to bed) one of us picks up Ruby without waking her up, holds a bottle to her lips, and she just intinctively starts sucking so has a feed while asleep. She'll take however much she needs. We always warm this bottle slightly.
We don't burp her afterwards as she is so relaxed she doesn't gulp in any air when feeding.
We just put her straight back to bed afterwards.
It's done so your baby will stay asleep longer because it will be longer until they wake for a feed.
We've either dreamfed or woken Ruby up for a feed when we go to bed ourselves, since birth and she slept 10pm-5.30pm from 4 weeks, 10pm-8am from 6 weeks and these days 7pm-7am.
btw some people on here have said their babies refuse the dreamfeed though
Ruby used to, so we just woke her up. Eventually she dreamfed.