This section applies to: the making of the appropriate general plan; any part, amendment, extension, or addition to the plan; the protection of and the carrying out of the plan; and the exercise of any: planning, zoning, or subdivision control powers in the regional district; and other powers granted in this title to the Commission or to the Montgomery County Council or the Prince George’s County Council. The purpose of the plan is to: guide and accomplish a coordinated, comprehensive, adjusted, and systematic development of the regional district; coordinate and adjust the development of the regional district with public and private development of other parts of the State and of the District of Columbia; and protect and promote the public health, safety, and welfare.