Follow this guide by Patricia McConnell at reinforcing yourself as the decision-making and loving owner, helping her realize she does not run the show.
This has been thrown around a lot on the sub lately. What has been debunked is the concept that dogs are constantly trying to "dominate" you, that they see humans as fellow dogs, and that wolf packs in the wild have steadfast "alphas." What has been found is that dogs are still pack animals and thrive on existing in cooperative groups, but "the leader" role is a lot more fluid than once thought and can be situational. They also don't tend to see humans as other dogs, making it unnecessary to try to imitate their behaviors and "Establish dominance."
However, I personally, along with many other renowned trainers such as Patricia McConnell, still believe you need to exhibit calm, consistent leadership to your dog, since they are still group-oriented animals and respond to having rules and boundaries, just like children, and just like horses. These boundaries just don't need to be enforced with extreme aggressive tactics as some trainers once thought. My third time recommending it, but Ms. McConnell has a great quick and easy-to-understand guide about how to be a leader to your dog in a loving, non-aggressive way. . It's very inexpensive, and easy to refer to in the future (I have dozens of times over the past decade).
I'm like the poster child for this, but I highly, HIGHLY recommend you give this guide a read before bringing home any new dog of any breed. If you do nothing but give affection to a dog and don't offer any sort of training (sitting, giving paw, etc. are mostly just tricks, not learning how to actually be a quality canine member of society), ANY dog can be come aggressive, anxious, stressed, or hard to live with. The guide is written by Patricia McConnell, who advocates for loving, parent-like, common sense training for your dog. She has many other books, but this guide is like $3 and maybe 25 pages long. If you want your new dog to be successful, enjoyable, and happy, PLEASE take it to heart.