Just go ahead and use the keyboard for navigating the uefi bios, it shouldn't be hard to press tab to drop to the next column.
If I'm right, either page up or + raises the value, page down or - lowers the value setting in the submenu.
Hitting escape will move you back one page where you were before in the bios or all the way back to the main screen.
Only use the mouse if you're trying to adjust a particular setting where the keyboard if you press a button by mistake will send you back to the wrong menu.