After holding some trial seminars, the instructor should look into the legal standing of such events and thus steer clear of the gray economy and tax evasion. Although few authorities are likely to take interest in someone just starting out who has not yet had a chance to inform them of his activities, it’s best to comply with any requirement to do so. Keeping everything compliant with applicable regulations will save you a lot of headaches and stress in the long run, especially if you make it big in the field. Newly-minted instructors who are late with paperwork for one reason or another often treat any incoming funds as voluntary donations.
The issue of incorporation is one for the instructor and/or organizer to work out on his/their own. Due to the fact that laws and business-registration procedures vary from place to place, it is not feasible to provide any specific advice in that department here. In order to follow all the rules and avoid mistakes and problems with the government from the very outset, it’s recommended that one consult legal advisors who can explain what to do, how to do it, and in what order to do it.