Congratulations on the imminent arrival! We tried to avoid accidents in the crate by taking our pup out regularly, but if she did wee in it the bottom tray protects the carpet. We just made sure we had plenty of cheap fleecy blankets we could rotate.
We started crate training straight away. We fed her in the crate and tossed treats into it - with the door open - so she’d have positive associations. Also, we bought a Snuggle Pup - a heated soft with a heartbeat sound.
I’m ashamed to admit I took the wrong advice initially - a friend told me they left their puppy to cry and in a few nights they were sleeping through. I tried this and my pup cried more and more each night! After that I slept next to the crate, which I wish I’d done from the start!
First, I settled her to sleep but left the door open and lay next to it. Through the night she crept into my sleeping bag and slept all night. The second night I placed the puppy in the crate and shut the door but slept next to it. The next night I moved a little bit further away, and so on and so on, until eventually I was on the sofa. When the puppy woke I took it out to the toilet. Then settled it back in the crate with lots of cuddles, much like you would a baby. Took it in turns with other family members to sleep on the sofa and take her out to the toilet as and when.
Then I progressed to sleeping in my room with a baby monitor, and going downstairs when she woke to take her out and then settle her back down again. If she whimpered, sometimes me speaking to her through the baby monitor was enough for her to go back to sleep.
During the day time, from day 1 we left her in the crate (door closed) and left the house, just 10 mins at a time. We set up a puppy cam to keep an eye on her. We built it up gradually every day.
She’s now 3 and sleeps in the crate (door closed) every night. If we leave the house for any length of time she also goes in it. It’s really handy as we can take her anywhere or put her to stay with anyone - we just pack her crate.
I read that if the crate is too big the puppy is more likely to pee and tear up their bed. If it’s small, they’ll feel more secure. Ours is the size of her dog bed, with blankets over it to keep it dark. She has room to stand and stretch, but not to walk around.
Good luck!