Again there are a few ways to find the idea here. First trace out the lines from Black’s king. On the f-file you see a Black pawn, Black queen, White bishop, and White rook. The White rook is most significant because it drives up the file and has the power to exert a pin. Of course it doesn’t do that now; the possibility is there, though, because of the structure of the file. What would it take to realize that potential? Well, two of the pieces in the way can be eliminated together: if White plays BxN, Black has to reply QxB to avoid losing his queen to White’s rook via discovered attack. Presto: now White has a pin on the f7 pawn. Immediately you consider what the pin was protecting. Answer: the bishop on e6. Can White now play BxB? No, not quite yet: Black’s queen, now on e5, would be protecting it. But this can be cured by exchanging away the guard with QxQ, d6xQ. Now Black’s bishop is free for the taking.
The point is one we have seen before: don't overlook possible pins because there are pieces cluttering the needed line. Think about ways to clear them and ask what would then be possible. This includes cases where the dividend of your maneuvers is a mere pinned pawn.
Another way to see the idea would be to observe the pressure on the e5 square occupied by Black’s knight. It’s attacked twice (by White’s bishop and queen) and guarded twice (by Black’s queen and d6 pawn). When you see an evenly guarded square like this, you may not be able to win the piece that sits on it; but you still have the power to control the look of the board by initiating the series of exchanges those attackers and defenders are poised to make. Imagine liquidating the position and ask the usual questions about the resulting position. Here that means White pictures 1. BxN, QxB, 2. QxQ, d6xQ. Those exchanges are a wash, but when you imagine the board as it then would look and trace out the enemy king’s lines, you see that a pin of the f7 pawn would have come into existence and that it would leave Black’s bishop on e6 loose. It's worth reinforcing a few times in your mind’s eye.