So just to be clear on the 'order' of events per God's Word...
1. the placing of the IDOL abomination in a rebuilt stone temple built by the Jews, kicks off the time of "great tribulation" Lord Jesus forewarned of. The first part of the Dan.9 "one week", a period of 1260 days, has already been completed by this point of this idol abomination being setup in a temple in Jerusalem. The placing of this abomination in the new temple in Jerusalem represents the start of the latter 1260 day period of Daniel's "one week."
2. Jesus said for those of His in Jerusalem to get out of Judea when they see that "abomination of desolation" idol in the temple at Jerusalem. He also said for those of His in the countries to not enter into Jerusalem in that time.
3. During this time of "great tribulation", the coming pseudo-Christ to Jerusalem will exalt himself as God, and over all that is called God, or that is worshiped. That means he will sit over ALL religions upon earth. Jesus proclaimed him attempting to pass himself off as The Christ, that he would work great signs and wonders so deceptive, that it would, IF it were possible, deceive even His own very elect.
4. God's two witnesses will appear in Jerusalem and prophesy against the beast for 1260 days. The Gentiles will tread the holy city for 42 months. Both periods represent the "time, times, and an half" of the Book of Daniel for when God's servants will be persecuted prior to Christ's future return.
5. Then after the 1260 days, God's two witnesses are to be killed in Jerusalem by the beast that ascends out of the bottomless pit (i.e., Satan, the 'dragon'). Their bodies will be left unburied. Then 3.5 days later, they rise.
6. Next event is Christ's coming on the 7th Trumpet. This will end the 1260 days time of "great tribulation".
7. Then 30 days after the "great tribulation" of 1260 days, the 1290 period will take place.
8. Then 45 days after the 1290 days, the 1335 day period will take place, and those who come to it are blessed.