There are plenty of how to install dashcams on youtube its pretty much the same for any camera / brand.
Position center and as high as you can on the windscreen, but do remember to leave a little room so you can slide it off its mount if need be, if you have a dotted area on top of windscreen that's cool as it will hide most of the dashcam then.
No need to focus, dashcams bar one i know off ( lukas ) are fixed focus, so nothing you need to do there.
The main issue i think are making sure your camera are installed on the windscreen in a nice horizontal way, this can be a little tricky if you have to install it off center due to some silly sensor housing there, still the wide angle lens should make sure you record what you need.
I will try to make a install video in my car when i get the DC, but by then a lot of other people should also have gotten theirs, though most of those probably wont be bothered with making a install video.