Existing pet doesn’t like a new dog.

There's a lot to unpack here but I'll Try and be very brief basically your new Dog does not like the new puppy first I Think you're doing a great job by Managing your older dog and the puppy And not putting them in the same room Together even if it has been weeks Because I think that's important for Some dogs that you not rush the process So you're doing the right thing give it Time until you feel like the time is Right it really is not uncommon for many Dogs to need days weeks or even months To feel comfortable with other dogs Every dog is an individual you may want To start creating positive associations With both dogs by having them in Separate rooms or with a baby gate and Doing some basic training with one so That they can experience existing with Each other in the same area you may also Want to consider taking walks together So that the dogs can experience being Together in a state of normality in Other words it's probably a good idea to Get the dogs comfortable with existing Around each other before they meet and Take it slow nothing wrong with Involving a professional trainer who Uses modern methods and does not use