SPST rocker switch wiring for LED strip
The switch used in the video  youtube.com/watch?v=cQpQWFYX524 is a lighted SPST switch.  It includes an LED connected between one switch terminal and the third pin, as below.







simulate this circuit &ndash; Schematic created using CircuitLab

A plain SPST switch (no light) will only have two terminals.  An unlighted switch with three terminals would be SPDT.