Nouns and pronouns are either singular or plural. Nouns typically form their plurals by adding ‑s, (boys), ‑es (torches), or ‑ies (cities). Some plural words, like children and fish, do not use -s. Pronouns have special forms to show plurality (I and we, he and they, it and they, she and they) (examples in subjective case).
If the grammatical subject of a sentence or clause is plural, then the verb must appear in the plural as well. The plural form of a verb (other than the verb to be) is the base infinitive form (I write and they write, I am and we are).
Be careful, some writers form plurals by adding “apostrophe ‑s.” You should use the apostrophe only when there's no other way to form the plural, as in Dot your i's and cross your t's). To form the plural of an acronym or initialism, just add ‑s, as in He has two IRAs. The same is true for dates, as in the 1960s.
Finally, a plural subject is formed with the coordinating conjunction and (John and Mary have decided to move). Words like along with, together with, as well as, and others do not form plural subjects. These expressions are not coordinating conjunctions. Thus: John along with Mary wants to move.