Where should I start?
Read through the tutorials one by one
Go through the subject topics in the indexes and go through the links
Refer to the PPB list
There is also a list of references pinned to the top of the FB group
How do I know what drugs are used in HK?
IMPACT for antibiotics
PSHK booklet (quite old though 2011)
You can also refer to MIMS HK and the Poisons List
For the list of references in the FB group, there are so many, which one first?
Just as a suggestion the HK Reference Frameworks for hypertension and diabetes are really well laid out and local references you can start off with these to warm up.
Another HK guideline I recommend you read through eventually the is the antibiotics guidelines IMPACT, although this is more of a challenging read it is worth the effort.
There is so much to study, I'm overwhelmed!
If you give yourself enough time to prepare it will be fine. Start small to begin with to warm up your brain muscles. Try using some of the tips in the Brain Hacks Course such as visualisation.