Hi!!
I have no experience in sheep, but I have some experience in goats and milking.
It all depends on if you want to put up with the 'hassle' of milking her!
After a week or two, depending on the mother's production some people will separate the mother from the babies for the night and milk her in the morning, then return the babies to her for the rest of the day and repeat.
You would need to be sure that all three get enough milk from her though, I don't know how big your ewe's udder is.. but this way you would only milk once a day.
OR
You could remove the babies completely and bottle feed them and milk the ewe twice a day.
OR
You could just leave then all with her, as long as they all get their turn.
If you decide to remove the babies and bottle feed here is some info, geared towards goat kids but can be used for lambs, has info on feeding amount, getting the babies on a bottle, etc;
http://fiascofarm.com/goats/feeding.htm#bottle
Depending on your goat's behavior it might be really easy to milk her, or very hard.
If you have a milkstand it usually helps to feed them on the stand while you milk. If you don't have a milk stand you might have to put a collar on her and tie her to a fence to milk her.
To get a first time milker to let down her milk you might have to massage her udder, sing to her, talk softly to her.
When we first started milking our very first goat years ago we had to hold her rear end and back legs in place so she wouldn't kick, she hated having us touch her udder! About after a week of doing this she realized it wasn't so bad and that she got fed and got to have a raisin and turned out to be a great milker.
Is that what you wanted to know? Am I missing anything? I know i am but I don't know what..