Metz 48 af-1: Not sure how to use?

I got a Metz 48 af-1 flash a while ago for my nikon d3000. And I'm not 100% sure on how to operate it. It did come with a user manual… But it's All in german or something, which i obviously can't read.

I have been using it, but i'm still completely clueless at times.
I have observed that the flash only goes off when the flash button lights up green
Lately the button hasn't been turning green very often… Ruins a lot of good shots because no flash will go off

I'm mainly wondering if there's any special way or thing I'd need to do to make the flash go off
like is there a special setting, or i don't know.anything.

I also don't know what the TTL flash mode really does. What's the difference between TTL and M (manual?)

The green light is the ready light, after the batteries have charged the flash capacitor enough to take a photo.

If the green light takes longer to come on, your batteries are getting weak.

TTL means "Through The Lens" and it is a metering system that from instructions from the camera, regulates the proper light output. For that reason, you can simply point & shoot without having to put the camera or flash in manual mode.

Also TTL generally results in longer battery life. When you shoot manual, full power is always produced by the flash. In TTL, the power is reduced by what the camera actually needs, so the batteries don't have to recharge the flash capacitor as much.

You should be able to download a new manual from either the Metz website, or the Manfrotto website (they are the US distributors for Metz). The manuals will be multi-language, and the English section is about 4th in line.

So look at your manual again - perhaps you gave up before you got to the English section.