Can't produce metric dimensions with the Dimension Tool

Running Mac OS on MacBook Pro and new to SketchUp. The default seems to be Imperial and I can’t find the options to change this.
Thanks

Window>Model Info>Units

Life saver. Thank you Dave.

You’re welcome.

FWIW, there are templates already setup with metric units. You just need to choose the right one. Or you can make your own template after changing the units to suit.