Sequential switches are underrated modules, I would say they are perhaps the most modular of all..! Exactly because of that, there are quite a few different uses.
To wrap your head around the module I would advise you to plug several sound sources (VCO, filtered noise, more filtered noise, percussion) into the I/O 4 jacks. Send the O/I output to your systems master out and plug a clock signal into the trig in. You can understand the module as a 4-step spectral sequencer! Verbos has some wild examples here:
One step further: do the same, but send the output of the seq switch through an enveloped VCA into the the FM input of another oscillator!
You can do the same thing with rhythms. Plug 5 different trigger patterns or clock divisions into the 4 I/O jacks, and a slower clock source into the trig in. Send the O/I output to a drum module/pinged filter/LPG/envelope.
You can also use the seq switch the other way around. For example: Patch multiple sound sources into VCAs without envelopes. Send an envelope into the O/I jack of the seq switch and patch the 4 I/O jacks into these VCAs. Maybe send a funky rhythm into the Trig in. Now the envelope will open another VCA every time the seq switch switches.
Some ideas for melody:
And don’t forget you don’t need to use all I/O jacks. Leaving an empty space can yield the most interesting results!