help

help + base form
He helped organize the event.
He helped organized the event. (wrong)

help + to + base form
He helped to organize the event.
He helped to organized the event. (wrong)

help + noun/pronoun + base form
He helped us organize the event.
He helped us organized the event. (wrong)

help + noun/pronoun + to + base form
He helped us to organize the event.
He helped us to organized the event. (wrong)

help + in + -ing form
He helped in organizing the event.
He helped in organize the event. (wrong)
He helped in to organize the event. (wrong)
He helped to organizing the event. (wrong)