Feeling your pain, Jia! We've just been through it with our puppy-- we got him at 16 weeks and have had him for almost 3 months now. I would say it was a month-long process for him, to get really comfortable and crate-trained.
For starters, I have a feeling that all dogs are different, so just because I had a pretty easy time doesn't mean it's because I did all the right things-- a lot of it has to do with the dog, too, so please don't get discouraged and keep trying to figure out what will work for your puppy. For example, my puppy has never, ever howled-- now, who knows why? maybe it will come later in life for him. However, he can bark very, very loud, starting from Day 1 when he was barking in the car as I took him home. A very mature LOUD bark. However, there have only been 2x when he has used this loud bark. Once when he had to stay at the vet's (obnoxiously loud) and once when my roommate was home but had him in the crate-- he apparently barked x 45 minutes (as my upstairs neighbor told me). But other than that, he has never used that bark (thankfully) when he's in the crate. He would just whine to show us he was upset. Usually he would whine anywhere from a few minutes to 10 minutes each time we put him in the crate that first month; then he would curl up into a ball and give us a sad-mad look, and then fall asleep.
I should also tell you about my friend, who crate trained her chihuahua and told me to crate-train mine. Her chihuahua barked and barked and made all sorts of noise for 3 days straight; then decided it wasn't worth it to bark anymore, and never made a sound again when put in her crate. Crate-trained in 3 days, despite all the obnoxious barking! And actually loves going into her crate now, and even goes in by herself at times. So, it can happen.
I had to read all about crate training, because I didn't know a thing about it. One thing I read that could be helpful in your situation, is that it made the suggestion to alert your neighbors that you just got a puppy and are in the midst of crate-training it now. Meaning that it could be a very loud and annoying process, but only this bad for a short time. You could explain the process usually takes weeks to months (or for my friend, only days!), and that once it is done, the puppy should not typically be that loud anymore, and that many puppies are quiet once they are crate-trained (mine is totally silent). Anyways, it could be helpful to open that line of communication with them, if you have a decent relationship with them, maybe even giving them a gift card or small present as a token of your appreciation for their patience (if you feel inclined to do so). Bottom line is that it could be helpful to explain that this really shouldn't be a long-term situation, just a temporary one.
Other things we did, which you may or may not find helpful: we didn't just have him in the crate when we were gone or sleeping (first month, he slept in his crate in the living room). We also would put him in there for a half hour or an hour, several times a day, on weekends, for example. And we would be in the same room with him doing other things around him. That seemed to help him not always associate the crate with us leaving him. We put a lot of comfy blankets and water bottle in his crate. We also have always put toys in his crate-- however, I have never seen him actually play with toys in the crate. He only seems to rest or sleep in the crate. I also used to feed him his dinner in his crate, occasionally, since he looovvves food! I would put his bowl in it with the door open. He was so excited about the food, he would go in and eat it, and then come out when he was done. Just so he can associate the crate with good things. Couple times a week, I would also give him a beef rib bone or other chew/bone toy that he could work on and eat over a period of 30 minutes or so. I would put it in there, he would go in, I would shut the door, and he would be preoccupied with working on it (so definitely no barking or whining for a half hour!). Also, it was cleaner for him to eat the bone in the crate, rather than on our carpet. We did ignore him when he whined. And when he quieted down, we would come back and talk to him/play with him, and give him attention. Don't get me wrong-- he did NOT like to be in the crate and was mad at us. But when he did the right thing, we tried to reward him with our presence to try to make it a little more pleasant for him. When he was in the crate, sometimes we would try to play with him and pet him through the wires. Sometimes he would be mad and try to nip/gnaw on our hands and fingers. We didn't allow him to do that at all, and would absolutely ignore him and leave when he did that behavior. I think it worked because he doesn't do that now.
One thing I learned the hard way (though probably intuitive for a lot of people)... I felt like I was breaking my back, trying to put this 20 lb pup into the crate that he didn't want to go into... shoving him in there and then fighting to close the door as he tried to get out. After a couple weeks of this, one day it dawned on me to throw a great-tasting treat to the back of the crate. I would show him the treat first and then he would follow me as I threw the treat in. My puppy would go right in to eat it, nose first, and then it was easy for me to close the door-- voila! So much easier. I liked giving him treats that would take him 5 min to eat (ie. chicken wrapped yams or dried chicken chews), because it would take him some time to eat it-- so he didn't turn around quickly, and because it would occupy him so he doesn't whine for at least 5 minutes. I think it helped make the transition easier, as he was calmer after working on the treat. Because i have heard bassets will do anything for food (... mine is that way...), I was prepared to give him the greatest-tasting treat, if needed, such as hot dog or steak (but fortunately, didn't have to, as he was fine with the dog treats).
A couple weeks ago, (I would have never believed this...!), he started going into the crate to nap in there in the evenings!!! unbelievable! (he sleeps in our beds at night). I think it's like his "cave" now, and I have no doubt it can become your puppy's too... it just takes some time. Hang in there and don't get discouraged. It really can work. Good luck with everything!