How to win a won position - rookie question

Looking for help from you guys.
I noticed I often have good position I can't turn into victory. The problem is that I really don't know how to go on, I'd say I miss the principles to play endgame.
I show you an example:



I'm black. I think my position is good: I'm up a pawn, king is way safer than my opponent's, my knight in c4 is great (at least I think) and Stockfish says I'm 3 points ahead. But I don't know how to turn this advantage in a victory.
Thinking white king is quite open I considered b5, but after a5 my bishop is worth nothing and I feel I'm stuck on the queenside.
On the other hand, the last bastion of white position are the central pawn, so f6 could be an option, but I open a file opponent can easily exploit with his rooks. I played a senseless move like Kf8 just waiting for an inspiration and - lucky me - my opponent resigned. But what should I have done? And why?

Thanks in advance,
L.

Well, in chess there's no elevator. You have to use the stairs. Developping technique takes years and decades, we all did that. You have a concrete position, play it some times against the engine. If you fail reverse the colors. Just continue your way with exploring your possibilites.

One tipp: at a certain point it is not enough to work with pieces, you have to use pawn levers. a6-a5 and the typical French f7-f6 come into mind. f6 is French standard, attackin the pawn chain at the front. Switiching your attention to the f-file, Rf8 and play down the new street. Practise!

You played well and you got a good, winning position for all the reasons you give yourself. ...b5 is of course no good, as it makes your own bishop worse. I dislike ...f6 too: as Nimzovich wrote: "you should attack a pawn chain at its base, not at its tip", but people do not like Nimzovich any more. The most logical is to prepare ...a5. You had an opportunity earlier 22...a5, but that is not bad, no harm has been done. I like your move 29...Kf8: it is useful to approach the centre with your king in the endgame. Also as Bronstein said: "if you do not know what to do, then wait for your opponent to get an idea: it is sure to be wrong." Winning a won position often requires patience: do not rush it. If it is a won position, then it does not matter how many moves it takes you to win it: you only have to exercise extreme care not to blunder it away. In fact it is often the losing side that blunders: it is very hard psychologically to defend a lost position. Here your opponent even cowardly walked away presumably fed up and disgusted by his own position in ruins.

The 'learn from your mistakes' button is a useful feature for this. Often when you think you've got a good position, it's because you missed a knock-out. (Not really the case here, mainly because white gave up really early - but it's still worth checking)