Turnkey design project and author's supervision are two different stages of work on an interior design project.
The turnkey design project includes developing a design concept, selecting materials, furniture and decor, creating an estimate, and planning all stages of work for implementing the project.
Author's supervision is a stage that follows the development of the design project and involves monitoring the execution of all project work, coordinating the work of contractors and staff, controlling the quality and timing of material and equipment delivery, as well as resolving all issues related to project implementation.
Thus, a turnkey design project is a complex of services for developing and implementing a project, and author's supervision is a stage of control over the implementation of the project that follows its development.