Hi there and
to the forums!
You've come to the best place to learn even more about budgies! We're here to provide the best possible advice for budgie care
You definitely should take the cotton out of the nestbox, as mentioned. If the eggs are fertile then you're going to need to put in some pine shavings after she's done laying.
FaeryBee has provided some excellent resources above, so be sure to read through them. Also, it's important that you're aware of all potential problems and every possible piece of information about budgie breeding as, if this clutch is fertile, you're going to have to do a lot of work to ensure it goes smoothly.
FaeryBee has asked some great questions. Also, make sure you read through every single breeding sticky that exists around here to ensure you're aware of everything
Definitely read through the others, too, as they include the forum's many stickies and articles to ensure that you're up to date on the very best of budgie care practices.
If you have any questions after reading through everything, please be sure to ask as we'd love to help!
Keep us posted on how things go.