Valinux, Welcome to the world of the ACE 250. Pretty good little detector. Keep at it with patience and just do whatever khouse says to do - you'll do alright.
To keep the 1969-D cent in perspective, though, lets look at a few things:
There were 4,002,832,200 circulation cents struck in Denver for that year. That's over 4 BILLION. Not very rare - and the cardinal rule of numismatics is "A Coin Must Be Rare To Be Valuable." There were no D mint proof coins struck at all that year, so you can discount that option.
The $4000 1969-D cent you refer to on the chart is one that is in full-red, MS-63 graded condition, as certified by PCGS. Keep in mind, too, that price is simply a guidepost.
In order to find a 1969-D cent that grades that high with a detector, you would have to do a few things.
First, you would need to separate it from an original, unopened mint roll - without touching it - and allow it to drop to something soft, like grass. Then, detect it... but dont rub your coil on it!
Now, immeditaely pick it up with clean cotton gloves, secure it in a sealed envelope or container and never touch it again.
Next, send it to PCGS and pay them to grade and encapsulate it. Without that certification, it is still just a shiny cent.
After all that, you would then have a one cent coin that "guide values" at $4000. It still doesn't mean it would sell for that, today.
I humbly suggest that your 1969-D cent, as dug from the earth, is worth about one cent. Maybe two cents, with todays copper prices being what they are.
I'm not being harsh here to be an @ss. On the contrary, I want you to get the correct understanding of these things early on.
It's just the reality of detecting circulated and lost coins from the earth, that the vast majority of them will fall far short of ideal. Don't pin your hopes too high in that regard.