You are right on track with what you are doing! Crate training is SO important, especially for young pups like yours. Make sure that the crate is always used as a positive tool and NOT for punishment! That is SO important!
To get your pup used to the crate, I would start out by feeding meals close to the crate door, and gradually start feeding your pup in the crate. The whole key is to have your pup associate the crate with GOOD things and not bad things. Make sure that you pair a word such as “crate” as a command when your pup goes into the crate on her own. NEVER FORCE YOUR DOG INTO THE CRATE! That will only harm any progress that you have accomplished and will hurt your relationship with Bella.
Throughout the day, toss some incredibly yummie treats in the crate, and using the word “crate”, have Bella go in the crate. Give her a few seconds in the crate before shutting the door. If she cries, let her do it. Ignore her! By giving in to the crying and opening the crate door will reinforce that all she needs to do is whine to get out. Then she will cry all the time! That isn’t what you want. Be careful giving her a treat when you let her out. That may cause Bella to cry more, as she is expecting a treat when she is let out of the crate. I would just let her out and acknowledge her after a few minutes after she calms down from the excitement of being let out. Just being let out of the crate is good enough for her!
Toss fun toys in the crate so she has to play “find it”. Make the crate training a game.
After awhile, start leaving her in the crate for short periods. When you come home to open the crate, make sure Bella is CALM, and make sure that you do not make a huge scene when letting her out. What I mean is, don’t love all over her, give her treats, talk baby-talk, etc. You want to make your comings and goings as uneventful as possible. That helps curb all the excitement and potential separation anxiety that so many dogs face these days. It sounds harsh, but our excitement to see our dogs and their excitement combined is a powerful combination that can lead to a lot of problems.
When you leave, a good idea is to toss some yummy treats in the crate for Bella. Soon, she will associate you leaving with snacks! I do not crate my dog (she has never destroyed anything in our house and does nothing wrong), but I still give her a few snacks EVERY time that we leave the house. It just reinforces that us leaving is ok!
Since you have a puppy, you need to watch what you put in the crate when she is in there and you are gone. Pups are chewers as you know, so you don’t want your pup destroying anything while she is in her crate and swallowing something she shouldn’t. A good idea is a strong Nylabone for chewing or a Kong toy. With a Kong toy, you can fill it with all kind of yummies and it gives Bella something to do for awhile while you are gone. Filling a Kong with soft food and then freezing it is even more fun for the dogs! I have frozen Kongs in my freezer at all times. Most dogs will sleep during the day, so once she is done with her snacks, she will snooze.
As long as you make the crate training a positive experience, never force her in there, never yell at her for crying (just ignore), and never use the crate as punishement, you will have success! Crates are our friends!
Best of luck!!