BAS is the acronym for Business Activity Statement. A BAS is a form issued by the ATO that need to filled in by all businesses who are registered for GST. These statements are usually quarterly but for some businesses these may also be on a monthly basis.
STP is the way the government wants businesses to report tax and super information to the ATO. If you have a chat to your accountant they can make sure you are meeting your ATO requirements.
This will depend on your business size and what you want to do with it. Popular packages include Xero, MYOB and Quickbooks.
To become an accountant you will need to go to university and study an accounting degree.
A SMSF is a superannuation trust structure that can be set up to manage your superannuation money if don't want to have your money in one of the traditional super funds.