Are you adding the selection of tracks you want into the Queue?
If not, then it will only play the track you select from the album (unless you click on the Play Album icon at the top of the album selection).
The trick with Volumio is understanding that everything is driven by the Queue column really. It can be a pain at first but is actually really useful if you just want to browse through various albums etc, adding tracks to the Queue whilst listening to what is already lined up.
A mainly digital setup with a musical amplifier and endearing 1970's speakers. A CD player that hardly ever gets used and a turntable that is good enough to remind my how enjoyable my old vinyl is. Some cables and things.