If you register the trademark, no one else will be allowed to register or start carrying on business under that name after the date of your trademark. However, you can't use that to block someone who is already using the name. Shareholders own a stake in the business but they do not automatically have the right to operate the business. If your shares are voting shares, you typically do have the right to cast your vote in deciding who will be directors of the company. However, not all shares carry the right to vote.
Directors are the people elected by shareholders to operate the overall business of the corporation.
This last group of people is determined by the directors. The articles of incorporation of a company is the document that sets out the the basic setup of the corporation. It may also say whether the business the company can carry on is restricted. A properly drafted set of articles requires the help of a knowledgable lawyer. Bylaws are the rules of procedure that a company needs to follow when conducting internal business, such as calling and holding meetings of directors and shareholders.