why is the cone of light not showing

trying to do an event style night light.
could I get some advice or a link to a tutorial please?
I thought that checking off the “cone” would provide the effect I was looking for.
But it actually did nothing.
Thank you

Hi, Show Cone is for 3dviewport, switch on “Halo” near by.
This is for rendering.

Cheers, mib.

Thank you!
Will go try it out.