How to drive a speaker with amplifier using 3.5 mm jack
The symbols circled in red are the ground connections
VI is the input voltage
VS  is the supply voltage
VT  is the threshold voltage for the mute capability. From the datasheet, VTneeds to be between 1.9 and 4.7&nbsp;V to turn muting off.
C5  is the 0.1&nbsp;µF capacitor
Two 8&nbsp;&Omega; speakers in parallel would equal the 4&nbsp;&Omega; load shown


You could use this schematic, from the datasheet, which does not have the muting capability:


  


As Elliot points out in their comment, the manufacturer has marked the TDA1905 as obsolete.