you need to enter country (state), then town, then street and then street number (or intersection). Second time you search you only change street (if the town remains the same) or town (if country remains the same and town changes). At the end of the search you select what you want to do, i.e. Navigate, if you want to start navigating to that address.
When street numbers are available in the map data then you can search for it, for example New York/Manhattan/5th Avenue. Unfortunately house numbers are frequently missing in free maps, but are available in TomTom maps.