I have a Leviton dimmer 057 with 2 black and 1 green wire. How do these wires
Connect to 1 black and 1 white wires going to a light?

Thanks

That is a switch loop circuit. Check to see if the dimmer has a load and line side, some do.Then you need to find out what wire supplies current to the box, it could be white or black although it should be white marked with black. Hot to line side of the dimmer, other wire to load side, green to ground.