From Nahjul Balagha, we read that `Ali (ra) tells us to pray the five prayers in their respectful times.
-`Ali (ra) says in: [A circular about prayers to the governors of all the provinces.] Nahjul Balagha page 582:
Arabic:
أَمَّا بَعْدُ فَصَلُّوا بِالنَّاسِ الظُّهْرَ حَتَّى تَفِيءَ الشَّمْسُ مِنْ مَرْبِضِ الْعَنْزِ وصَلُّوا بِهِمُ الْعَصْرَ والشَّمْسُ بَيْضَاءُ حَيَّةٌ فِي عُضْوٍ مِنَ النَّهَارِ حِينَ يُسَارُ فِيهَا فَرْسَخَانِ وصَلُّوا بِهِمُ الْمَغْرِبَ حِينَ يُفْطِرُ الصَّائِمُ ويَدْفَعُ الْحَاجُّ إِلَى مِنًى وصَلُّوا بِهِمُ الْعِشَاءَ حِينَ يَتَوَارَى الشَّفَقُ إِلَى ثُلُثِ اللَّيْلِ وصَلُّوا بِهِمُ الْغَدَاةَ والرَّجُلُ يَعْرِفُ وَجْهَ صَاحِبِهِ وصَلُّوا بِهِمْ صَلاةَ أَضْعَفِهِمْ ولا تَكُونُوا فَتَّانِينَ
English:
[Lead the Zuhr prayer till the shadow of a wall becomes equal to the height of the wall, the Asr prayers can be performed till the sun is still bright and enough time of the day is left for a person to cover a distance of six miles. The Maghrib prayers should be performed when people break their fasts and when Hajj pilgrims return from Arafat. And the time for Ice prayers is when the red glow of the even twilight disappears from the West, till one-third of the night is still left. The morning prayers are to be performed when there appears enough light of the dawn for a man to recognize the face of his companion.]
-`Ali (ra) says to his son Muhammad (ra) in: [ When Imam Ali (a) appointed Muhammad bin Abu Bakr as the Governor of Egypt, he gave him the following instructions. ] Nahjul Balagha page 526:
Arabic:
وَاعْلَمْ ـ يَا مُحَمَّدُ بْنَ أَبِي بَكْرٍ ـ أَنِّي قَدْ وَلَّيْتُكَ أَعْظَمَ أَجْنَادِي فِي نَفْسِي أَهْلَ مِصْرَ، فَأَنْتَ مَحْقُوقٌ أَنْ تُخَالِفَ عَلَى نَفْسِكَ ، وَأَنْ تُنَافِحَ عَنْ دِينِكَ، وَلَوْ لَمْ يَكُنْ لَكَ إِلاَّ سَاعَةٌ مِنَ الدَّهْرِ، وَلاَ تُسْخِطِ اللهَ بِرِضَى أَحَد مِنْ خَلْقِهِ، فَإِنَّ فِي اللهِ خَلَفاً مِنْ غَيْرِهِ ، وَلَيْسَ مِنَ اللهِ خَلَفٌ فِي غَيْرِهِ. صَلِّ الصَّلاَةَ لِوَقْتِهَا الْمُوَقَّتِ لَهَا، وَلاَ تُعَجِّلْ وَقْتَهَا لِفَرَاغ، وَلاَ تُؤْخِّرْهَا عَنْ وَقْتِهَا لِإِشْتِغَالٍ، وَاعْلَمْ أَنَّ كُلَّ شَيْءٍ مِنْ عَمَلِكَ تَبَعٌ لِصَلاَتِكَ.
English:
[O Muhammad, son of Abu Bakr! Remember that I have entrusted you with the command of the most important section of my army which is Egyptian. Do not allow your whims and passions to overrun your judgement. Keep on guarding and defending your religion and the State given under your trust. Take care that not for a single moment in your life, you incur the Wrath of Allah, to gain the pleasure of any person. Remember that the Pleasure of Allah can substitute the pleasure of everybody else and it will be the most beneficial substitute for you but His Pleasure cannot be substituted by anything. Offer your prayers in their respectful times, do not rush through them, and never delay in offering them. Remember that piety and nobleness of all your activities are subject to sincerity and punctuality of your prayers.]
– end –
Online link for Reff 1.
أما بعد فصلوا بالناس الظهر حتى تفئ الشمس من مربض العنز (1) وصلوا بهم العصر والشمس بيضاء حية في عضو من النهار حين يسار فيها فرسخان (2). وصلوا بهم المغرب حين يفطر الصائم ويدفع الحاج (3) وصلوا بهم العشاء حين يتوارى الشفق إلى ثلث الليل.
وصلوا بهم الغداة والرجل يعرف وجه صاحبه. وصلوا بهم صلاة أضعفهم ولا تكونوا فتانين
http://shiaonlinelibrary.com/%D8%A7%D9%84%D9%83%D8%AA%D8%A8/1109_%D9%86%D9%87%D8%AC-%D8%A7%D9%84%D8%A8%D9%84%D8%A7%D8%BA%D8%A9-%D8%AE%D8%B7%D8%A8-%D8%A7%D9%84%D8%A5%D9%85%D8%A7%D9%85-%D8%B9%D9%84%D9%8A-%D8%B9-%D8%AC-%D9%A3/%D8%A7%D9%84%D8%B5%D9%81%D8%AD%D8%A9_82
For reff 2:
وَاعْلَمْ ـ يَا مُحَمَّدُ بْنَ أَبِي بَكْرٍ ـ أَنِّي قَدْ وَلَّيْتُكَ أَعْظَمَ أَجْنَادِي فِي نَفْسِي أَهْلَ مِصْرَ، فَأَنْتَ مَحْقُوقٌ أَنْ تُخَالِفَ عَلَى نَفْسِكَ (5) ، وَأَنْ تُنَافِحَ (6) عَنْ دِينِكَ، وَلَوْ لَمْ يَكُنْ لَكَ إِلاَّ سَاعَةٌ مِنَ الدَّهْرِ، وَلاَ تُسْخِطِ اللهَ بِرِضَى أَحَد مِنْ خَلْقِهِ، فَإِنَّ فِي اللهِ خَلَفاً مِنْ غَيْرِهِ (7) ، وَلَيْسَ مِنَ اللهِ خَلَفٌ فِي غَيْرِهِ. صَلِّ الصَّلاَةَ لِوَقْتِهَا الْمُوَقَّتِ لَهَا، وَلاَ تُعَجِّلْ وَقْتَهَا لِفَرَاغ، وَلاَ تُؤْخِّرْهَا عَنْ وَقْتِهَا لِإِشْتِغَالٍ، وَاعْلَمْ أَنَّ كُلَّ شَيْءٍ مِنْ عَمَلِكَ تَبَعٌ لِصَلاَتِكَ.
http://nahj-balagha.blogspot.com/2012_04_23_archive.html
It is true that Hazrat Ali never advised his subjects to merge Zuhr and Maghrib prayers with Asr and Isha prayers at all times.
How did ali(ra) pray namaaz
Like all Muslims pray Namaaz.