Remove the dad at once, the female can get pregnant again very soon after giving birth. Aside from that, leave the babies alone, do not touch anything, do not disturb the cage apart from to give food and water (try keeping this at the other end of the cage from the nest), and remove the wheel. You may also want to pile some more bedding material like torn up toilet roll (fluffy cotton wool type bedding is bad for hams, although if you have some in the cage at the moment I'd leave it until the babies are old enough to be handled before removing it) at the other end of the cage from the nest, so mum can make the nest bigger if she wants. Feed the mother high protein treats such as mealworms, cooked egg white, boiled chicken etc. Once the babies have opened their eyes at about two weeks, you can start handling them (and post pictures for us!) -- and clean the cage, as it'll probably need a clean by then!
There's a guide to sexing Roborovski hamsters in the Robo section of the forum -- once the babies are around four weeks old you should split them into single sex groups to prevent something like this happening again