before applying to get a puppy, what should i do ?

so to preface this, im all for adopting instead of shopping, but most, if not all, the local shelters only have bully and/or larger/high energy breeds of dogs, which does NOT fit my lifestyle, as well as the fact that this is going to be my first dog.

the breed im looking at getting are cavoodles, which research says is suitable for first-time dog owners and suits my lifestyle. i've found some breeders online who i'm considering, but on the site, there's the option to ask them questions or directly apply to the breeder, which is where i've got quite a few questions.

i know that there should be questions that i should ask the breeder to ensure that i'm getting it from a responsible breeder, but do i do this for all the potential breeders that i'm going to choose? what type of questions should i ask if i'm only talking to them online? (im aware i should ask to see parents and the living environment, but how do i do this when it's online? do i ask to go visit them?) when am i supposed to ask to see the puppies, parents and their living environment (ie before applying to them, after applying or after applying AND being selected? should i apply to the breeder before the puppies are born or wait until after they're born?

is there some sort of step by step guide or advice/comments people can share that i've missed out on? cus again, this is my first time BUYING* a pet and the people around me either adopted their dogs, didn't do much research or their parents bought their dog when my friends were younger, so they dont know too much.

would love if someone could point me in the right direction!

*^(for those interested, i got a rabbit from a family friend cus they didn't want her anymore and just dropped her off at my house the day after i agreed)