Then when the Horn is blown with one blast (69:13)

Almuntakhab Fi Tafsir Alquran Alkarim

When the trumpet is blown once or sounded and all those in heaven and on earth are dumbfounded

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(69:13) So *10 when the Trumpet is blown with a single blast

Then when the Horn is blown with one blast meaning

*10) While reading the following verses one should keep in mind that at some places in the Qur'an the three stages of Resurrection which will occur one after the other at different times have been mentioned separately, and at others all the three have been combined and mentioned as a single event. For example, in Surah An-Naml: 87 the first blowing of the Trumpet has been mentioned, when everyone will be suddenly struck with terror. At that time they will witness the general confusion and the upsetting of the order of the universe, as described in Al-Hajj: 1-2, Ya Sin 49-50 and At-Takvir: 1-6. In Surah Az-Zumar: 67-70, mention has been made of the second and third blowing of the Trumpet. On the second blowing of it everyone will fall down dead, and when it is blown for the third time, all dead men will rise back to life and present themselves before Allah. In Ta Ha: 102-112, AI-Anbiya': 101-103, Ya Sin: 51-53 and Qaf: 20-22, only the third sounding of the Trumpet has been mentioned. (For explanation, see E.N. 78 of Ta Ha, E.N. 1 of AI-Hajj. E.N.'s 46, 47 of Ya Sin). But here and at many other places in the Qur'an all the events of Resurrection, from the blowing of the first Trumpet till the people's entry into Heaven and Hell, have been described as a single event.
 

Then when the Horn is blown with one blast meaning in Urdu

پھر جب ایک دفعہ صور میں پھونک مار دی جائے گی