I didn't find one I was completely happy with, so after some trial and error I found out how to insert eyelets and decided to make a tutorial myself.
I bought this packet of eyelets from Prym.
They come with some "how to's" at the back, looking simple to do; but it doesn't work out that way; especially with thick layers of fabric.
The eyelet has two parts: a flat part (1) and one with a - sort of - colar (2) .
I started with marking the inside of the eyelet on my fabric.
Then, I punched a hole , with my Prym "Vario pliers",
It is much easier now to start cutting a larger opening.
This may be a bit scaring, but go slowly and nibble away small pieces until your hole is slightly smaller than the eyelet .
Insert your eyelet part 2, through the hole. The fabric should stretch over it.
Then, you need the tools from the packet and a hammer!
Hammer firmly but carefully and your done!
Here is the inserted eyelet!
Just let me know if something is not clear enough for you.