It’s different, it’s always been republican, what do we have to learn from it.
Wikipedia’s page on the constitution. As we’d expect it has citations, but not that many, and less in English. Amazon has a couple of books which might help. It describes itself as a Confederation where the Cantons have autonomy and their own constitutions. The right of citizens to initiate referenda is embedded. I have also bought “Swiss Democracy: Possible solutions ….”; there is more now i.e books than once.