First thing you need to do is raise the decimal. Once you've raised the decimal then you should continue through the problem as if it were a standard long division question.
Start with the first number which is 6.
6 divided by 3 is 2. That means you can subtract 6 from the first number.
Then, you bring down 3 and do the same thing.
3 divided by 3 is 1. Subtract 3 from 3 and then bring down the next number.
Finally, 3 divided by 9 is three.
By following this process, you should get 2.13 as your final answer.
Look at the image below for more reference.