The question asked what is sirat and how is it?

 The question asked what is sirat and how is it? 

Alhamdulillah, الصراط means path. 

Allah says in Quran, 

Maryam 19:71

وَإِن مِّنكُمْ إِلَّا وَارِدُهَاۚ كَانَ عَلَىٰ رَبِّكَ حَتْمًا مَّقْضِيًّا 

And there is none of you except he will come to it.[1] This is upon your Lord an inevitability decreed.

Scholars say this refer to the sirat which is the bridge.

And everyone will pass through it and under it is hellfire and when one is able to pass it will enter Jannah.

And the sirat is very thin like the hair and sharp like a blade and everyone will pass it depending on his deeds.

Some will pass it like lightening, some will pass like the speed of a wind.

As reported in Hadith,

Narrated As-Suddi:

"I asked Murrah Al-Hamdani about the saying of Allah, Mighty and Sublime is He: There is not one of you but will pass over it (19:71). So he narrated to me that 'Abdullah bin Mas'ud narrated to him saying: 'The Messenger of Allah (ﷺ) said: "The people will pass over the Fire, then they avert it based upon their deeds. The first of them (would pass over it) like a flash of lightening, then like the wind, then like afleeing horse, then like a rider fleeing on a mount, then like a man fleeing, then like one walking."

Jami'at At Tirmidhee

Vol. 5, Book 44, Hadith 3159.

As reported again,

Then a bridge will be laid over the (Hell) Fire." Allah's Messenger (ﷺ) added, "I will be the first to crossit. And the invocation of the Apostles on that Day, will be 'Allahumma Sallim, Sallim (O Allah, save us, save us!),' and over that bridge there will be hooks Similar to the thorns of As Sa'dan (a thorny tree). Didn't you see the thorns of As-Sa'dan?" The companions said, "Yes, O Allah's Messenger (ﷺ)." He added, "So the hooks over that bridge will be like the thorns of As-Sa-dan except that their greatness in size is only known to Allah. These hooks will snatch the people according to their deeds. Some people will be ruined because of their evil deeds, and some will be cut into pieces and fall down in Hell, but will be saved afterwards, when Allah has finished the judgments among His slaves, and intends to take out of the Fire whoever He wishes to take out from among those who used to testify that none had the right to be worshipped but Allah.

Sahih al-Bukhari 6573.