Whilst the assistant in the android google photo app you can easily create an album, on both recent photos on the phone and also the photos on-line. On the web access the assistant is unfortunately blanked out (at least at the moment) and with an obtuse message that you are all caught up and up to date. However the very clean (aka very few icons and tools visible) google photo view doesn’t have an obvious way to create an album. Yet it is still simple to create albums but you have to select the photos first. After selecting at least 2 photos you will see some extra icons on the selection bar and then you need click on the + Plus Icon on the right hand side of selection bar.
You now have the option to create a new album or add to an album.