This Sudoku solving method builds upon the previous "Obvious pairs" technique. However, instead of being based on two numbers in the notes, a "Obvious triples" is based on three. This is the only difference. To understand it better, let's look at an example.
Let's look at the top-left block. Its three bottom cells contain the notes {1, 5}, {1, 8}, and {1, 5, 8}. This indicates that these three cells must contain the numbers 1, 5, and 8, although we don't know the specific location for each number yet. What we do know is that 1, 5, and 8 cannot be placed in any other cell within this block.
Therefore, we can remove them from the notes of those other cells.
This is how to use the "Obvious triples" solving method when solving Sudoku.