UPDATE:
I dont know what i did, i rebooted MineOS and then in Networking there were TWO options…
eth0 (Which was already there before the reboot)
wlan0 (??? Guess it has something to do with wlan 
)
But if i select wlan0 and do the automatic setup it still doesnt work
As iMelsom posted, same issue
Dunno, so look for a unbutu distro that supports both your machine and wireless dongle I guess. (click the blue line for the full page.)
Sound advices to be found from both hexparrot and iMelsom at that link above.
So just to clean everything up!
- I can access the Web Interface!
- I can download anything I could possibly download
- The Thing that annoys me, is that I need the LAN on my main PC, and the WLAN Dongle on my MineOS PC
- I already got wlan0 somehow, but cant do anything with it
- LAN (eth0) works great, but as explained I need it on my main PC
- All I need is to get the WLAN Dongle working, but the explanation should be in following Language: Noob-Approved
EDIT: And I hope i dont annoy you with many posts, I just dont speak English that good
So the router (modem) has only one LAN (RJ45) jack? And can not be connected to wireless?
Yes, it has only one LAN Jack.
And if i get the second question right, No I cant connect my Dongle to my Router.
(Or if I get the question other, No i cant connect my Lan to wireless :D)
PC can not connect to router wireless?
yes I was going the other way.
the simple answer is dongle on pc (easy to install driver)
with lan cable to the server
Yes that would be the simple way, but unfortunatley my PC doesnt like the WLAn Dongle… 
so i get big lags while playing on Mineplex, or playing Leauge of Legends…
as above, (high up), it is likely that your dongle is not supported, that means you either have to install the support to the server or start over with a flavor of unbutu that supports the dongle and the server hardware.
I would expect the same performance if you did start serving minecraft over the dongle.
So you mean, I should search a driver (One question is it possible to install a drier with apt-get install /// /// ?) on the internet?
Maybe it is also because Windows 10, but if i test it on my brothers pc it works great!
That driver and instructions should work.
On the PC, do you have both onboard intel video chip and also a seperate ati rage or nvidia card by chance?
Yes in Device Manager> Graphic Cards, i have these:
Interl® HD Graphics 4000
NVIDIA GeForce GTX 660
What does this have to do with my Internet?
Because I am not good enough at linux commands.
But I know hardware. you intel grafix card is screwing you causing the lag with the dongle, ROTF!
What because you are not good enough at linux commands? Do you mean You dont know because…?
lelel Intel the troll ( ͡° ͜ʖ ͡°)
Right I can not help with installing the correct kernal but that website can.
But try this first, just a minute. let me think