Good device, but be careful for the laity!

I must preface that I am EDP technically a layman and with networks, IP addresses and encryption systems poorly versed.
Maybe that's the reason why the device did not go immediately to me and even caused major problems.
Perhaps this helps my review laymen among buyers.

I run several computers through a router. One of these computers is wired (LAN), the other kablelos (WLAN) connected. I want the D-Link like the wireless signal strengthen (repeater function).

So I have to unpack, inserted after the manual CD and start the installation. First surprise: The special surface can indeed set in German, but once you're on the router, everything is in English and can not even change !!!
I have chosen the automatic installation and was then invited to put the cable into the computer. Since I run the computer via the router and therefore no computer connection was free, I plugged the cable into the router. And that started the disaster: The installation was not working. Simultaneously, the installer has made sure that all my computers suddenly stopped coming to the Internet. To my dismay, I also did not come on my router to check for configuration or to change.
As I said, I am a layman and first did not know what to do, or what it may be.
Long story short. After about 2 hours and a number of telephone conversations with friends I came out that the program at my computers (even those who were only connected via Wi-Fi) has entered a fixed IP address. When I had that (in turn help received from friends) away everything went again. Only not the D-Link!
So I sat down on the internet and researched.

Here is my advice for laymen like me because the device is apparently not easily plug and play:
Be sure the German manual from the network load.
Not running the silent installation, but the custom installation.
Then it's quite simple and you will be guided through the settings.
If you want to operate the device as a repeater, select only the repeater mode and then select the device to be amplified from the list and click. All settings are then taken (not first manually adjust something and then select the device! That did not work for me).
Then just enter the password for the network and you're done!
Caution: The device must be placed somewhere necessarily where it receives a good signal. If the device is too far from the router, for example, other devices that use the D-Link get though a wonderfully strong signal, but do not come to the internet !!!
The latter drove me almost to despair before I understood it. Now the D-Link is in my 1st floor and amplifies the signal from the top floor to the ground floor wonderful.