If you just don't have time or haven't had your coffee yet, here is the briefest possible summary of Acts 15 from the One-Law perspective:
The issue before the Jerusalem Council was: from whence does covenantal salvation come? Some Pharisees said from circumcision (15:1), Peter said from grace and faith (15:9,11). Peter also posited that Gentiles had joined Israel, becoming “a People for His Name”(15:14, Note: only Israel is called by His name, Deut. 14:2; Isaiah 63:19). The council concluded that Peter’s argument was correct (15:14) because it agreed with the Prophets (Amos 9:11-12 (LXX); Zechariah 2:11; Isaiah 2:2-3; Isaiah 45; Isaiah 56:3; Isaiah 45:21-22 (LXX), Isaiah 56:6-7 (MT); Micah 4:1-2; Jeremiah 31:31-33 (LXX); Ezekiel 36:25-27) . Given that Peter, the Prophets, and the Council deemed Messianic Gentiles to be saved by grace (contra the Pharisees of 15:1) and "turned" from paganism to join the G-d and People of Israel, James used this newly-established jurisdictional authority over the Messianic Gentiles to order them to desist from contextually-linked, pagan practices (i.e. the Fourfold Decree) that they might now cling to a Judaic sphere of influence (15:21, “law of Moses”).