We will approach the language from a point of view known as structured programming. In much the same way that human language is composed of sentences and phrases, and they in turn are composed of nouns, verbs, pronouns, and punctuation, computer languages are made up of functions, statements, constants, variables, and operators. We introduce these below. A statement is a command to the computer to do something. In common practice, declarations are typically referred to as statements.
Statements are the equivalent of a sentence in human language.
Comments can occur anywhere within your code. They are not interpreted by the computer. They exist merely to inform someone reading the source code about what it is doing. It is wise to make liberal use of comments. Things which seem crystal clear to you when you first write them often look like the deepest sort of magic when you return to maintain the program.