Best friends & Sisters Leah & little baby Blossom 🌸💕 my girls

Hello, could someone help me with tips on what to do to introduce a puppy to two cats. I'm trying to introduce a foster puppy to my cats and I feel like I'm messing it up. I left a tshirt out that I rubbed all over the pup so my cats could know that pup's scent. The cats already have a bit of a strained relationship between them, one is big, bully and a male, the other is smaller, female and timid. I just taped netting between the room the puppy is in and the rest of the apartment.

I opened the door a bit, the pup got excited I assume and barked and made growly sounds and got a bit too close trying to push his nose through the netting, my timid cat had just been observing the pup so far but she started hissing quite a bit. My bully cat came along and went close to the netting later..but the pup had already retreated by then.. My cats have a history of a strained relationship whenever my bully gets insecure, he redirects his aggression on my timid baby. The cats have been seeing and hearing the pup on and off for two to three days now, seeing her through a crack in the door on and off and the pup howls quite a bit. Added a video of my timid cat and the pup, I didn't capture after this when the hissing started as the pup wanted to come out.

I take it with a grain of salt of course, but Gemini has me believe that I have completely ruined the introduction. Two good points that I got from there - give the cats some higher ground to stand on when looking at the pup, and keep a barrier between the pup and net so the pup can't access the netting.