I'm completely new to this and the offers in my country seem much lower, but I'd like to give it a try.
Just so I get things right, you open an account in a bank, keep it open long enough to get the bonus, close it and then do it again (open an account in the same bank I mean)?
Or does it work only once per bank?
Most banks have a rule that you can get a bonus every two years, some more, some less.
Make sure you read and save the rules. Take screenshots. I've needed to refer to them plenty of times, and I've also needed them to send to the bank customer service rep because sometimes they don't know the rules of the promotion you signed up under.
Also keep track of the date you close the acct so you can "churn" it, which means getting the same bonus again.
I've also used the screenshots successfully when forwarding complaints to the Consumer Finance Protection Bureau, but that's a US thing.
Also, it's generally considered "best practices" to leave an account open six months before closing. Some bonuses have terms that state they can claw back the bonus. Otherwise, the thinking is not to piss off the banks so they stop offering free money.