Joining tanker!

What is the procedure for joining a tanker for the first time?
I got TWIC
I got MMC oiler.

BST and Lifeboat

There is a lot I am facing. I have sailed on container vessels already. Now when I came to this country, I had to take all the documents certified by the coast guard and obtained the TWIC & MMC oiler as entry level. All I am waiting to have an opportunity to join but I don’t understand how to start and where from to start applying for the shipping companies!