You look up a street name. That entry tells you which street it begins from. If you don't know that, then you look up one further. And repeat until you get to such a main road you'd know it even after looking at a map.

So basically you'd look up the street and then browse back and after you'd have a sort of gps like instructions. "main road until you see X street, then turn there, then drive until you see Y road" etc.

I had several in the car I drove, for all the nearby cities/towns. Many in same covers. So it'd cover the main city and outlying towns. Never had to use a map. (Although again, I can if needed.)