Well, it's a big topic, so let's start slowly.
Here's a start.
Finites: verbs that change form. e.g., She walks, she walked.
Predicators: Everything but the subject; e.g., I had cake today.
Direct Object Complements: the verb's object; e.g., Max sent an email.
Indirect Object Compliments: the verb's other object; e.g., Max sent me an email.
Intensive Compliments: What traditional grammarians called a relative clause (RC); e.g. Max sent me an email that his boss had sent him. An RC describes a noun. In our example, the noun phrase is an email.
Subjects: The doer or topic of the verb; e.g., Max sent me an email. An email was sent.
Do you have any questions?
Student or Learner