Why? Two ways you make babies. With momma, and without.
Easiest and typically most reliable for beginners is with, let her carry them and "spit" fry. Common practise for most mouth brooders.
The other, is stripping them. And dropping eggs into an egg tumbler. This is usefull for pushing production, and getting parents back into breeding shape. This takes more skill, and if you goof, you may risk losing all fry.
Very difficult to keep them from breeding though, they are more prolific than bunnies.