If I want an event to recur every Monday, Wednesday and Friday, how do I do that?
You can click on "Add task" and when the input box opens, in the bottom-right corner of it, you'll see a field named "due date". Here, you can type in many types of dates incl.: "every Monday", "ev Wed" or even "every Mon, Wed, Fri".
For a full list of supported due dates please refer to this page: http://todoist.com/Help/timeInsert