> If you’re booting the UEFI installer, you highlight the install
> option in the installer boot menu and press E to edit. Repeat the
> change as above, but add it to the end of the line starting with
> “linux”. Press F10 to boot.

Thank you for the detailed instructions, but
I am still having problems.

I have a choice of "graphical install" and "install"

With "install" I have added "nomodeset" so that the
line reads

> linux (vmlinuz) vga=788 --- quiet nomodeset

When I press F10, the next screen has what looks like
a row of small images across the top, with the rest of
the screen completely blank. I have tried typing
ctrl-alt-F1 etc, which makes some changes in the images,
still most of screen blank. I can only exit by typing
ctrl-alt-F4 followed by ctrl-alt-del.

If I choose "graphical install" and add "nomodeset"
the result is more frightening. I get a completely
blank screen. ctrl-alt-F and ctrl-alt-del don't
seem to do anything. I can only exit by unplugging
the computer!