Cooking Chef is a time-management game: customers arrive with orders, you prepare each dish through its steps, and serve before they lose patience. The pressure comes from parallelism — several dishes at different stages at once — rather than from any single task being hard.
Earnings go into kitchen upgrades that shorten cooking times and let you hold more orders, which is what keeps later levels possible.
Parallelise — start the slowest dish first and prepare quick items while it cooks — and upgrade cooking speed before anything cosmetic.
They leave without paying, which costs both money and your rating for the level.
Yes — tap to cook and serve. Nothing to install.