Hi Ndarbey, welcome! Congrats on adding a new pup to your home, too. :dogtongue2: Always fun adding a new family member. I've had multiple dogs..I currently have three..my whole life (I'm older than dirt :msngiggle

, and if your dogs are getting along well, I'm sure things will be just fine. Give them time to settle in together and establish their relationship, stepping in if/when you need to. Since your new pup is young, you'll undoubtedly need to spend time with her alone on training, etc - so make sure you also spend 'alone' time with your older dog. If you ever feel your older dog needs a break, don't hesitate to give them a time-out from each other, just use a baby gate, a crate, or whatever you use in your home. If you don't use either, consider it. With multiple dogs, it's a good idea.
You said your pup is larger than your older dog, but didn't mention breed, weight, etc, so I have no idea of the size difference. If it's a huge difference, watch them closely, as if play gets wild, the smaller one could get hurt accidently. More info would be helpful.
You'll get the hang of it in no time, and I bet they'll become best friends and be wonderful company for each other. There are loads of great people on this forum, so ask any questions you have, someone will jump in. Most importantly with your new pup, have lots of fun, make sure you spend lots of time with both (and each one seperately, also) - there's lots of love to go around!