I'm playing through Baldur's Gate 1 right now (after finishing PoE) and it's not even comparable imo. These DnD rules make no sense and THAC0 is the stupidest thing conceived as far as I'm concerned.
To your post though. Do you have 6 party members yet? If not, make that your first priority otherwise the game will be a slog for you. Some enemies are not meant to be fought the first time you see them. You usually need to come back later with a full party to stand a chance. If you hover over the stats on any screen like the item or character details it literally gives you a breakdown of what each and every attribute does and how it contributes to combat.
What part of the game are you at and what mechanics don't you understand?
If it's the herbs you're missing there is a vendor for them in