Hey, thanks for your feedback.
It was my idea too, to try to boot it from USB first, before removing Windows (i dont want to have 2x OS).
My colleague got the same notebook (HP Probook 650 G3) and he tried the Ubuntu 18.04 TLS and said to me that he got some problems with the energy management and the trackpad. So i guess i'll try the 18.10 with the newer kernel