Conjugation is a very long word, isn't it? In grammar, when you conjugate a verb, it just means that you change the verb in order for a sentence to make sense. Correctly conjugated verbs communicate ...
A conjugated verb is broken down into I, you, he/she/it, we and they. For example, the verb ‘to be,’ conjugated in the present tense is: I am, you are, he/she is, we are, and they are.
Subject-verb agreement means that your verb must be conjugated, or changed, to fit (or agree) with the subject. Subjects can be singular or plural. Think of singular and plural as mathematical ...