I’ve had dogs for over 30 years, but I am always nervous when we bring home a new pup. It’s completely normal and if anything, shows that you care enough to want to really try to get things right.
OP, I brought my latest pup home 4 weeks ago and I was nervous too. Most importantly, try to relax and enjoy her. They are only little for a short time and all she really needs at first is to learn that you are her people and that she can trust you to have her back. Lots of love, cuddles and fun. Swapsies when/if she gets hold of something you don’t want her to have, distract from things she’s heading for that aren’t a great idea and reward her generously when she gets things right. Keep things calm at home and limit visitors at first, while she learns it’s her safe place and gets use to your routines. It’s all about love, trust and confidence, they’re your foundations to build a happy confident dog
As others have said, take her outside every half an hour for toiletting and reward her when she goes. Ignore any accidents indoors. You will gradually get to know her pattern/timings, which means it gets easier.
Naps are absolutely essential. Overstimulation is the main source of land-sharking and a well rested pup is more receptive to learning. If she struggles to settle, licking and chewing are the two activities that will help her calm down and start to feel snoozy. Lickimats (supervised) are good for this and my boy loves the ostrich tendons and bones (which aren’t as stinky or messy as some chews) for a good old chewing session.
First and foremost though have fun!