1. Focused Reviews (imagine that this is your Hiragana schedule)
2. From Community Lists (the main lists)
3. I also have a list where I have them by column (you can pick multiple)
You're basically asking about targeted quizzing outside of the SRS (spaced repetition) intervals, right? If you're asking for the lessons, they're over here:
The schedule appears on your dashboard (literally, the home page).
If the schedule has something for you to study, there's a blue "Study" button.
If the schedule does not have anything to review scheduled for you, press the "Focused Review" button in gray.
Both give you the quiz, given how much the schedule is set in the settings, as dictated by how many terms you have in the schedule.
With "Focused Review" also under the three dot menu, you can bypass the 'Study" button that may or may not contain the materials Renshuu wants you to study. Regardless of which "Focused Review" path you take, you can use that to study as often you like at any time.