Open the Blocks tab. You'll see two sections.
Blocking Now shows what's currently restricted and confirms your blocking is applied.
Your Apps is where you choose. Tap a list to open Apple's app picker, then select the apps and categories you want in it. The picker is Apple's own, which is why it looks different from the rest of Aura and why it shows categories as well as individual apps.
A word on picking. Most people block too much on day one, hit a wall by lunchtime, and turn the whole thing off. Start with the two or three apps that genuinely eat your day. You can always add more once earning coins feels normal.
Selecting a whole category, like Social, catches apps you install later too. If you'd rather decide app by app, pick them individually instead.