I think pregnancy only prepares you for labour. Whatever comes after is unchartered territory - especially the first time, but also subsequent ones because they are all individuals and will all be different.
The only thing I can really say is to bed down and take things easy. There's so much pressure to be supermom, and its just not necessary or helpful. Do what comes naturally, trust your instincts and don't panic. The early days are the precious days, they don't stay newborns for long. Have long baths with them, cuddle and feed them, don't put them down, gaze at them - if that's what you want to do.
If you want to leave them sleeping while you go and have 10 minutes to yourself, have someone else care for them while you walk around the block three times to clear your head and just BREATHE, take the opportunity to go and buy a pint of milk just on your own, anything to let you come up for air and take a breath, give them a bottle if you are struggling, just put them down because they are doing your head in, then do it.
Just do whatever works and don't feel guilty. You will love them, maybe you won't get a rush of unconditional love in the first 3 minutes (I have and haven't), but you will love them unconditionally regardless. It might get foggy, you might get frustrated and angry with them (God knows I do) but you will be mothers, and from what I know of you all in this short time, damn good ones.
Sorry for the long post, but I just want you all to feel OK and not worry!