Threatens the bishop and forces black to decide to take the knight in exchange for the bishop or retreat... Why allow the choice though, what about Qg3 pinning the bishop to the king, black can't move the bishop and you are then threatening to attack with the pawn next turn gaining a peice

black retreats and attacks the troublesome white bishop, the exchange is slightly favourable to black as it would leave his rook in control of an F file free of pawns and also opens up the possibility of Qb6+ again

?? Highly questionable, white has offered to exchange the only two peices able to protect the king. Black is a peice up and should accept the trade.

Black declines the trade in favour of collecting more material. He is also stopping white from playing Qg3+

White retreats and reveals the renewed attack on blacks bishop. Black should exchange bishops to continue his attack on whites king

Black attacks the bishop but also is doing so at the same time as looking to create some space on the A and B files where white is vunerable

white accepts the trade of pawns allowing black to begin his final positioning towars the mate of whites king

Black takes the pawn and also attracts the bishop to retake, it looks like a free pawn but what if black plays Qb3 after... the bishop is pinned

white has accepted the pawn but the only peice defending whites king is now the prone white bishop, black can chase this peice around as there is nothing supporting it

Black begins his final assault, by chasing the bishop away he is preparing for... yes you guessed it Qb6... FINALLY