For anyone wondering, admonitions work by placing some text inside these pairs:
#+BEGIN_CAUTION
#+END_CAUTION
#+BEGIN_CENTER
#+END_CENTER
#+BEGIN_EXAMPLE
#+END_EXAMPLE
#+BEGIN_IMPORTANT
#+END_IMPORTANT
#+BEGIN_NOTE
#+END_NOTE
#+BEGIN_PINNED
#+END_PINNED
#+BEGIN_TIP
#+END_TIP
#+BEGIN_VERSE
#+END_VERSE
#+BEGIN_WARNING
#+END_WARNING