If we're talking specifically about “getting a license” it's very complicated. What kind of casino do you have?
Usually an advertising campaign is launched first on some related gambling topic, but authorized.
And after a few days of work can gradually add the headlines you need and use cloaca of course.
As mentioned above, you need:
1. A strong google advertising account with spending.
2. a good cloaca to redirect targeted traffic.
3. Security, such as an anti-detect browser, but a VPS is better.