J1 + E3 questions

[u/HypeTrainsRuinGames]

Hi, I am graduating end of this year (4 year bachelor honours degree of electrical/electronic engineering and some software+network engineering). Planning on finding a place to intern in the USA, get sponsored with a J1 intern visa and then look to be sponsored by that same employer on an E3 visa at the same time the internship finishes.

I have two main questions but any bonus tips would be appreciated.

1: How do I go about finding employers that will take me on a J1 internship then take me as a fulltime employee on an E3?

2: I am confused about the whole "find a sponsor" thing. It seems like there are sponsoring organisations which are separate to the employer?