I am doing a fresh install of High Sierra on a 2015 iMac. I am running the install off a current installer file on a USB drive. The wireless mouse is not connecting. The keyboard only works with basic commands like Spacebar (as return) and Tab (to navigate around the screen), and arrow keys. I was able to get to the "Select Disk' screen of the installer, but now the keyboard is not working at all. I cannot select the iMac internal drive as the install location as there seems to be no way to press 'return'. Any suggestions? Thank you!