In English, the most common way to make a singular noun plural is to add s.

One might think that the same approach would be used to make singular forms of verbs into plural forms.

That is not the case, however, and actually often the singular forms of verbs will end in s while the plural forms of the same verbs will not.

Basically to know which form of a verb is singular and which is plural, you need to know about that verb, though I can say this. The present tense third person singular of most verbs has an s at the end.