Hi, I have successfully re-lactated once when Niamh was three weeks old, and I am now doing so again after thinking I wanted to stop, but as MervsMums pointed out I am addicted!
You need to invest in a good pump, and some fenugreek tablets as well as stocking up on some oats and other foods that are high in protein and carbs.
Start by expressing
every two hours for 10 minutes at a time. Only use one breast at a time. You should also do this through the night too, as 2am-5am is when you milk production peaks.
Don't be discouraged if you get nothing when pumping. The point is that every two hours you are stimulating your nipples and glands, not that you are producing lots of milk. Even when I was BFing Niamh full time I could never express much
Before you give Marissa a bottle, put her to your breast. Don't be upset if she doesn't BF the first few times. Let her smell you, nuzzle you, play with the breast, etc. It's all about getting her used to being there again. If she does want to BF then great! Keep her there as long as she wants to be.
If you find she has trouble latching, then try having a warm bath with her and BFing there.
I've written a journal on re-lactation which you might find helpful. We had to battle through nipple confusion too, which is a seperate issue so let me know if Marissa is refuses the breast and I can give you some advice on that too.
Good luck!