If you had recently installed Unity Hub and Unity 2018, you would find that there is no option to select a location of your choice. Unity Hub first installs in C:\Program Files\Unity Hub, and after you select your Unity version from Unity Hub (I reckon you would select Unity 2018), Unity will then be installed …
You have a point light source behind some walls. Although you have enclosed the light, indirect light from the light source seems to seep through especially on the ceiling and the floor. It’s really just a Shadow Type setting that needs to be set right. Here is how to fix it.