I have diagramed the Lord’s Prayer in Matthew 6:9-13 (See below). I have diagramed the adverbial clause “as it is in heaven“ in v.10 to show it modifying the main clause as believes it’s telling us the manner in which the Fathers will is to be done on earth (I.e your will be done on earth just like it is done in heaven). Secondly, I also believe the same thing to be occurring in v.12 (I.e forgive our sins in the same manner as we have forgiven those who have sinned against us).