Hi Michael! Welcome to the boards!
You've come to a great place to get information!
A few quick answers:
If you want to be traditionally published, you do NOT find an illustrator for your book. The editor and art director of the publisher will find an illustrator for your book if they want to publish it.
After you write a PB, it is recommended you get people to critique your story. Getting some outside eyes on your story can help you improve it and decide if it's ready to be submitted to a publisher or agent. You can find some critique partners or groups in this thread:
https://www.scbwi.org/boards/index.php?board=73.0Or, since you are an SCBWI member, you could post your story in this thread to get some feedback as well:
https://www.scbwi.org/boards/index.php?board=121.0.
Once you feel your story is ready, the next step would be to decide if you want an agent or if you want to submit directly to publishing houses. This board is a good place to look:
https://www.scbwi.org/boards/index.php?board=260.0Most large houses are not open to submissions from unagented writers, but several smaller houses are. Many people recommend you find an agent, though you will find that some writers have very successful careers without one.
I hope this helps. There is a wealth of information on these boards. Take some time to explore! Two other websites where you will find great information on writing for kids are:
https://www.underdown.org/http://www.kidlit411.com/Best of luck!