Not for building or running the site. A coding agent installs AtarCMS, builds it from your answers and walks you through launch, asking you before anything that needs your decision. Editing content afterwards happens in an admin made for people who are not programmers.
What you do need: a coding agent you can run (on your computer or with SSH access to a server), and some patience to answer its questions and review its work. A developer helps if you want custom features beyond what AtarCMS does out of the box.