158. Aleinu

25:5 One should try to recite the Kedusha of Uva l’Tziyon with the congregation. If someone arrives in shul while the congregation is saying it, he should say it together with them before he says his own prayers. (Shaar HaTziyon 132:3 says that such is not our practice.) This Kedusha may be recited before the two verses that precede it. After saying the Kedusha, one should go back and say those two verses. One may certainly skip Ashrei and Lamnatzeiach in order to be able to say this Kedusha with the congregation, though afterwards he must say the prayers he skipped.

25:6 We then say Aleinu, which should be recited with proper reverence. This prayer was established by Joshua after the conquest of Jericho. Finally, the appropriate psalm of the day is recited.