This lesson is for participles that are not formed with -ado or -ido. The auxiliary haber remains regular; learn the participle itself.
An irregular participle example
hacer in Presente Perfecto
Common participles
abrir → abierto, decir → dicho, hacer → hecho, morir → muerto, poner → puesto, romper → roto, ver → visto, volver → vuelto.
Remember
The same irregular participle appears in every perfect tense; only haber changes.