Hi Emmanuele - somebody wiser and more experienced than me will probably be along in a moment to tell you this, but if you want to know who the legitimate publishers are, go to your local bricks&mortar bookshop and look at the shelves. Legitimate publishers are those that get their authors' books onto bookshop shelves.
Note down the publishers of books like yours. Go online and find those publishers' websites. Find their submission guidelines - this is another clue, because legit publishers don't make it easy to find their guidelines, and scammers do. Legit publishers make it easy to buy their books.
If any of those publishers accept unagented submissions, follow their guidelines exactly and send in your work. If they want queries only, send a query.
I think that's it.