The past participle for ' á' ' verbs is formed as follows:
1. Get the verb in its infinitive form:
mantecá'
2. Remove the ' á' '
mantec-
3. Then add a 'áu'
mantecáu
4. Join it to the verb 'havé''
llo ha mantecáu
In the next post I will explain how to form the past participle for ' é' ' verbs.