Start with main and Cargo
For a C developer writing Rust for the first time, the unfamiliar part is often not if, for, or function calls. The first real difference is the engineering entry point: C programs often begin with main.c, gcc, Makefiles, and argc/argv; Rust programs usually begin inside a Cargo project.
That is not just a tooling difference. Cargo manages source layout, dependencies, builds, tests, and package metadata. main also becomes more than a function returning an integer: error handling, standard output, standard error, and exit status enter the program structure early.