This is a quick instructional video on how to wire a 4x12 speaker cabinet in a SERIES/PARALLEL configuration.
When utilizing a SERIES/PARALLEL wiring scheme each pair of speakers is wired in series, then each series pair is wired together in parallel. When all four speakers have the same impedance, your final load will match. If you have four 16 ohm speakers, your final load will be 16 ohms, 8Ω will yield 8Ω and so on and so forth.
The style I use is similar to the way old vintage Marshall cabinets are wired.
The diagram shown on the video can be downloaded in the link below
https://drive.google.com/file/d/1W3XWhznL38baxz1KMn0OuoZ3ktb6KC5o/view?usp=share_link