boot - Failed Ubuntu 15.10 installation on UEFI system, how to report this bug

Yesterday I had to try installation of new Ubuntu 15.10 more than 5 times.

I have noticed methods that give me unbootable system on reboot after installation. It says it cannot detect UEFI partition even if it exist and is made during same installation time.

1. If I upgrade from 15.04 to 15.10 using Bootable CD, if ways half way saying it cannot detect UEFI partition


2. If I install using Something Else option during installation, it fails on reboot.

The only way for me to get bootable system was to erase whole hard drive and let it make all partition by itself (lost most of my data :'( forgot to backup in frustration)

I am very much confirmed of what I experienced yesterday (whole day) and I am pretty much sure that there is a bug in installer, so how do I report a convincing bug-report to Canonical?