Advice/ tips/ suggestions needed

Hi folks! I am planning on starting selling items from my small business on amazon soon. Even after reading blogs and watching several yt videos, I feel super clueless and overwhelmed.

I would really appreciate some advice or suggestions. Further, I saw 3 month free FBA for first time users…is it any good? It would also really help me out if you shared some of your experience and what u guys wished you knew when you started out!

Thanks in advance