On the SAT, the types of punctuation refers to commas, colons, dashes, and semicolons. One usage of colons and semicolons is to join two independent clauses that are closely related. A colon is used, however, when it elaborates on or clarifies what comes before it.
For the SAT, if you’re unsure if a sentence requires punctuation, it’s better to err on the side of leaving out punctuation. Only use commas, semicolons, colons, or dashes if you identify a situation that requires them. You’re more likely to miss a punctuation question by adding unnecessary punctuation than by leaving out punctuation that’s needed.