How do I start Xfce from the command line?

[Robert Moskowitz]

I have switched a system to multi-user with:

systemctl set-default multi-user.target

Now I want to startup Xfce, and I can't.

I tried startx and startxfce4

both failed.

How do I do this?  Or how do I go back to gui target.  at least temporarily?

thanks