it's a secret....

You can find them starting in Winter of year 1 after you get an event where a shadow person runs away from you at the bus stop. Follow the shadow person and find the footsteps they left in the snow that lead to a bush near the community center, then click the bush. You will find a magnifying glass.

From then on, you will be able to find secret notes while doing all sorts of activities: mining, hoeing, chopping trees, fishing... to read a secret note, select it and click on your character, as if you were eating an item.

Did you get the cutscene with the shadow person then follow their step and get the magnifying glass? Also I've found breaking rocks and fiber to give them more commonly. So maybe try farming fiber levels like 25 or 81

Happens in winter. Although PS4 and Xbox currently don’t have them if that’s what you play on

One of the first handful of days of Winter, you walk from your farm to the bus stop and it triggers. I think it's the 4th? Also note that you have to WALK, it will not trigger if you're on horseback. I figured that out the hard way.

You got a cutscene the first time you walked towards town in Winter year 1 where a little shadow fella ran off leaving footprints behind him.

They'll still be there for you to follow next winter.

It doesn’t have to be winter if you triggered the quest. I did it the following summer because I forgot about it.

That means you have not completed the Winter Mystery quest

Next winter, try going to the bush where he is hiding and interact with it. Maybe he’s still there even though you deleted it. 

You can’t get the stuff from the notes without the notes.

UPDATE: thanks for your help everyone! I just clicked on the bush Krobus was hiding in and the whole problem is fixed!

You really cant do any secret stuff without finding those secret notes first. Wait until winter again and hope for the cutscene to appear.

You need the secret notes.

Not sure it actually has to be winter, though. Try interacting with the bush in whatever season it is now.

stardew how to find secret notes - Google Search

Solution to your dilemma

You need to read them, and then they'll disappear from your inventory. You need one of them to unlock an event in the secret woods

I'm on switch, so I don't know Android controls at all. Sorry! I imagine it's the same way that you would use any other item in the game.

I believe the ragged note was >!written by the old mayor of little marrow!< but thats just about all ive got

Unfortunately there's no gold at the end of the rainbow :( the notes layout the events before the story takes place.

i feel like some of the notes have been written by ourself,, it mentions the loss of a woman, and the player has supposedly lost their wife 🤷🏻‍♂️

Hmm, I thought about this, and I do think that there might be some hidden lore, we should try to get game theory to make a video about dredge (unless I'm just being stupid and there is already one)

I need to go back to my file and check these off

You should still be able to get the magnifying glass by interacting with the bush by the community center (not sure if you need to do it during winter season or not though). In winter you would see footsteps leading to the bush.

Did you already shake the bush by the playground and see if he's there?

Thank y’all so much!!! I’ve been trying to figure this out for the longest time 😭

No, you can still trigger the cutscene with the shadow person at any time if I remember correctly although I think the ability to figure out how to trigger it if you don't already know only shows up in the winter season.