Can someone explain to me the whole service interval wrench and when to change oil?

I read the manual and tried searching but didn't find quite what I was looking for. I have a 2014 Jetta and am trying to understand the whole service interval thing that comes up when you push the time set button a few times.
I gather it means how many miles (or days with the clock thing) until the car wants to be serviced, but that seems vague to me. Does that mean oil, or do I just take it in and say the wrench appeared? Or do I just ignore it?
Also I can use the 1/2 switch button on the wiper stick to change between service interval 1 and 2. I don't quite get that either.
Also, for oil, is there any specific indication from the car to change it? Or do I just do it on interval? I looked at the dipstick and it has always been black which I read is normal from soot, so how do I know? I just got the car a few thousand miles ago, is it safe to assume the dealer changed the oil before selling it?
Again, all I've been able to find is how to reset it and I'm trying to understand how it works, and also the oil. For clarification, normal 2014 Jetta TDI (I think), the screen between the gauges is the one that takes up the middle third, not the tall one like on some other models/years. For oil info, I don't use high biodiesel blends.
Thanks

You need to service your car every 10k. Read your owners manual and you will see what needs to be serviced at that time.............very simple just follow the owners manual and everything will be just fine. I do not know why you are confused.

not only should you read the owners manual about 10 times until you can understand it but maybe you should also pick up the service manual for it as well it will have much more in depth explanation of things with pictures anyone can use. The forums here you can do a search for what oils to use, what are the best parts, who's birthday it is, searching and reading will do you about 1,000x more info than just a handful of us chiming in on your post. The forums are not as busy nowdays and you should also post this in the appropriate forum area for your car instead of 101.

Yes, you need to read it 10 times just to find the info.The maintenance system is certainly covered. Service interval sure seems like a 101 question to me. As to trusting that the dealer did any service, they will have records.
My partner drives a 2011 Honda, it's taken me 2 years to adjust to the maintenance minder paradigm. No printed mileage intervals at all. I think I like it. No idea how "good" the VW mm system is.

MichaelB said:

You need to service your car every 10k. Read your owners manual and you will see what needs to be serviced at that time.............very simple just follow the owners manual and everything will be just fine. I do not know why you are confused.

Click to expand...

This ^^^^

The service interval is 10k miles. Which 10k interval you land on determines what gets done.

What ALWAYS gets done:

oil change

tire rotation

general checks

Every 20k miles (so, every OTHER service... 20/40/60/80/etc):

Fuel filter

Cabin filter

Every 40k miles (40/80/120/160/etc.):

DSG service (if equipped)

Every 60k miles:

Air filter

Every 120k (or 130, depending on year):

timing belt

You'll also want to flush the brake fluid every 2-3 years, or with another normal service for convenience.

I changed our 1998 Jetta TDI every 20,000 miles per oil analysis. It now has around 270,000 miles and runs great!

Here is the pdf file for what needs to be done and when.

http://pics.tdiclub.com/data/500/2014_Jetta.pdf

Don't worry about the dash thing just learn this. You can read your manual and learn to work that stuff as you go.