I can help but it's outside the realm of my expertise.
>I'm going to try to write some children's books
Alright, if you have some good ideas run them by someone that you trust before going to the publisher.
I'm going to skip a couple of them because it seems like you have a good direction.
>I have a publisher in mind
Just one publisher?
If you have a decent book that several publishers like then shop around for the best deal. If you can only find one publisher to publish your book, you may not be getting a good deal.
>I don't really know anything about writing
Generally, there's a writing style that goes with certain books. Since you're writing a children's book, then you may want to write in a rhythming style. There are plenty of good resources for learning how to write in that particular style if you're interested.
>I don't know anything at all about getting a book published…
Write your book first.
Then when you're finished. Send an e-mail to the publisher telling them about your book. Give them a idea of what your book is about. Then if the publisher responds they will ask if you have a copy of your book and then ask for a copy so that they can review it.
>I don't know anything about marketing and getting a product attention and sales
You don't have to worry about that.
It's the publisher that does all the marketing and advertising.