Thank's a lot for your help.
There where no dipstick, but a level-plug.
Well, I opened that plug and out came some "oil" with the same color that my hair is turning now. :-)
Should the oil look like it is full of water?
This is not the case on other tractor I have seen.
Regarding the lift, it is correct - I had to put some weight on the arms.
And adjust the "locking-lever" that I found under the seat, on the left side just above the wheel-axel.