How's this?
If you want to do it this way, hold down the left <kbd>Shift</kbd> key while (re)booting so the GRUB boot menu appears. (If <kbd>Shift</kbd> doesn't work, use <kbd>Esc</kbd>.) With the arrow keys, select *Advanced options for Ubuntu* and press Enter. After this point you *won't* press <kbd>Enter</kbd> because that would boot normally rather than with custom boot options. Select any kernel and press <kbd>e</kbd> to edit its boot options temporarily. If there are multiple lines and your cursor is not on the line that starts with `linux`, move it there with the arrow keys. Add `in…