While the original text neglected to specifically outline the right to vote (other than saying the states were responsible for running elections), there are six amendments to the constitution expanding and clarifying the right to vote. One of these amendments is that senators must be elected by popular vote -- not out of a hat.
As far as your point about electors, that's just for the presidential election. Most elections you vote directly for the people running for office. Sometimes you even get to directly vote on policy matters (propositions or referendums).
You can download shared decks. On the mobile app, there's a little floating button with a plus sign that takes you to the shared decks, but I find it better to use the desktop app to import so that I can go ahead and fix any formatting issues I have too (i find the default font size to often be too small).