You can use our setup program (held in rNC nCoda Meta Repository) to kick-start your development environment. You'll need to register an account and upload an SSH key before you clone repositories from Phabricator, but you can also use our mirror on GitHub. (If you're not sure, start with GitHub; it's easy to switch later).
To browse tasks, choose "Maniphest" from the menu on the left, or use the nCoda workboard. The workboard shows many of the tasks we'll work on in the future, but some items are secret, and others are too vague, so you may not see a task for all of our plans. Every task starts out in the "backlog." At some point, we assign a task to a release (like "1610") and try to finish it on time. Releases are named for their year and month, so nCoda (Release 1610 (short)) will be finished in October 2016.
If you haven't seen our Discourse discussion board, you may want to take a look now.