Consider this...
Revelation 20:6,before the next age...
Revelation 20:6,before the next age...
Revelation 19:20,,,before the next age...
Revelation 20:3,,,,after the next age...
Rev.20:3 is when Satan and his angels are bound in the Abyss, which takes place just as Christ returns to the earth to end the age and establish the millennial age and after the beast and the false prophet are thrown into the lake of fire.
Revelation 20:12-15,,,after the next age...
All of the scripture, except for Rev.20:11-15, takes place at the end of the age and the beginning of the millennial age