**UPDATE**
So after a couple of hrs with no result i installed ubuntu linux and it worked perfectly, i kept working on it until my 860 evo ssd arrived, so i decided to continue the installation process with windows, i plugged out the HDD and installed the WIN 10 on the ssd, worked perfectly...
I installed the windows through the uefi prepared usb stick (used rufus), and made sure that all partitions are gpt.
in the case of boot mode (legacy+uefi)
when i pick uefi only mode, the hard disk disappears, and only the usb is left availabl.
So i brought different computer hardware and a second hand hard drive and built the pc, i installed windows 10 using a usb stick,the installation completed ,after restarting the pc and setting the proper boot orders, i get the "reboot and select proper boot device or insert boot media in...