Hello Tawhid. Thank you for your interest on SambaPOS project. You are right the quick start guide is just a starting point and there are a lot of features but unfortunately we don't have documentation in that detail. The main reason is even I don't know all possibilities as the lead programmer. On SambaPOS a lot of features abstracted like lego pieces and you can combine them as you need. Because of the abstraction level there are endless combinations so instead of talking about "features" we talk about "cases" here. For example someone asks how to configure SambaPOS for "happy hour" and if it is something very common we document the solution. In fact "happy hour" does not have the same meaning for everyone. So we don't have options like "Sunday Price", "Dining Price", "Weekend Price". SambaPOS even don't have "Happy Hour" feature. We have "price lists" and "triggers" that executes on certain times and activates a price list. You can use same trigger mechanism to e-mail reports to you at certain times or execute any other time based task. V2 version have some limitations because we hard coded most features there (for example payment options, accounts etc.). With V3 we removed most hardcoded parts and it is more flexible.
So Instead of trying to learn all possibilities focus on your needs and try to understand how to configure SambaPOS. When you can't find the answer we'll try to find a solution.