When to use the past participle vs the past perfect of a verb

Such as utilizar. If I said. “These verbs are used” I believe I would say “Os verbos são utilizado” but could I also say “Os verbos são utilizou”

If not then why?
Thanks for the help!

Just as in English, you can only use the past participle here. These verbs are used = Estes verbos são utilizados. Utilizou is the simple past, but it’s not applicable in this sentence.