Make a really cool multi-stage geocache

Have located a potential “false-positive” (easy-spotted decoy)
.

(Been wondering how to make it more than just a simple hidden box or jar.)
I think I can work with this.

(or a good place for a clue)
(Maybe 2)

I was telling my bro about geocaching, he said it looked like a waste of time, (socially speaking).
A half-hour later I found him in his room, (ALONE), playing a video game.

I was thinking of a scavenger hunt, & thinking of someone who may think it an utter waste of time, then thinking I want to use (most of) my time wisely. So I thought of geocaching & making a page of neat & useful bits of knowledge to leave in geocaches.
Obviously it should start out with a bit of information on yarrow. (I wonder if the people in Europe know of its awesome possible medicinal qualities. Don’t they have the Codex Alimentarius there which prohibits medicinal herb knowledge/use?)

Aint my idea, but I think it’s a really great one! ok now you have even less-of-an-idea what I’m talking about here.
But that’s ok.
All I need to add is maybe a starting place, and an ending place.

I found a geocoin, but I don’t know how to “activate” it. The coin has a code on it: [deleted]
I also have found a travel bug. Its code is [deleted]. I don’t know how to “activate” it either.
Perhaps they will be my “first to find” prize.

It seems like all those “brain games” and “lateral thinking” puzzles in those books; but you can never come up with one yourself.
I want to come up with something good/interesting; not just plop something into a decent hiding place. [edit: Perhaps I misuse the word ‘plop’ here; as I usually like finding others’ geocaches, and I’m sure they don’t ‘plop’ them down just anywhere. But it’s not enough for me.]
I think I’ve got a great “part” of it, but I don’t think I want to “start” there.
edit: A day later… [that reminds me of a time I was returning a movie; the attendant said, “It’s a day late.” I said, “What a coincidence, I’m a dollar short.” No reply – not even a change of expression.] Anyway, I went looking for things around town to talk about, giving clues to find my stuff. I’ll have to go again, b’cuz I was concentrating more on “waymarkers” than on “hiding places.” I found &/or thought of several interesting clues.
.
edit:another day later: “C.I.T.O.” I was in a grave yard, and I saw a beer can, and I picked it up, and was just about to take it to the car when I remembered that some guys take beer cans to their buddies’ grave; particularly if they were in a war together. I looked around, and sure enough, there was a grave very close that had another beer can on it. “The more you knowd”