Anyone any good at sudoku?

[BlingaRinga]

I need someone to explain this to me! Trying to do a sudoku on the NYT puzzle app and got totally stuck. The app will give you a hint as to which square to try to solve next, and you can also reveal the answer for the square.

The highlighted yellow square is the one suggested that i should have been able to solve, and 9 is the correct answer. However I cannot for the life of me figure out how I was supposed to figure this out - can someone explain!!

2 must go in the middle top column (highlighted purple) because it can't go on the left. Therefore, the 2 must go in the top left of the next square down and therefore the 7 goes on the middle row.

I had another crack at it this morning and finally finished it!

I think the bit I was missing was “this row/column needs an X, and it can’t go anywhere else so by default it must go here”