Seen and Saw
Saw is the past tense form of "see." Saw can be used by itself, without a helping verb.
You saw me. I saw that movie.
Seen is the past participle form of "see." Seen requires a helper verb, such as "have."
I have seen that movie. A coyote was seen in the park yesterday.
It is never correct to use "seen" without a helper verb.
I seen you. - Incorrect