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

Cheers, mib.

Thank you!
Will go try it out.
cheers!