Worked solution
Find the block that repeats
Look along the decimal for the group of digits that keeps repeating. Here the block repeats over and over.
Place the dots
In dot notation you put a dot over the first and last digit of the repeating block (a single repeating digit just gets one dot). The dots are a short way of saying "this carries on forever".
Write the answer
That is the recurring decimal written neatly with dot notation.