Focused review is probably what you want. Look for it next to the Study! (start) button. Depending on how you have things configured, it may be under the three dots.
What do you mean? If you learned hiragana on Renshuu, you should have a mastery schedule for it on your dashboard. If it's not there, go to your dashboard, click "Manage your schedules", and you'll find it in Japanese Basics under All Schedules. Click the plus sign to enable it. You'll get daily reviews, so keep the mastery schedule around for as long as you need it.
It depends. If you already have a hiragana scedule on your dashboard, the "focused review" button leads you to a quiz that reviews the hiraganas thaz you've already learned. If you don't have the hiragana scedule on your dashboard, click " Manage scedules" to add a scedule. You should find it under "All scedules" and then "Japanese Basics"
