My Aussie doesn’t understand no!

It probably wasn’t wise for me to choose an Australian Shepard as my first puppy. I’ve never trained a dog before and have been watching tons of videos. She’s only four months old but I’m staring to lose my mind trying to train her. When she does something wrong I tell her no and she stops or gets down or whatever and then goes right back to it a second later. Over and over again. I’ve tried distracting her with toys or whatever but nothing seems to help. I also cannot leave her alone for two seconds without her howling and barking. This makes trips away from home impossible. I don’t want to lock her in the crate to leave because I’m afraid she will start to hate the crate. Granted she doesn’t love it but she will go in there she just won’t stay in there. I stay at home 24/7 and feel like I should be making progress but am guessing I really don’t know what I’m doing. Any advise would be great on training.