Athinos is the ferry port for Santorini. It isn't pretty, it's a transport hub and not a place to hang out.
So as soon as we walked off the ferry we found a bus, got in, and rode up the cliff side.
The bus driver collected the fare later.
If you look to the lower left you can see the road starting up the cliff, then a series of switchbacks. Just to the right of the light pole you can see a bus on its way up.