At the time of the Prophet there was one adan before Imam comes to Menbar
The person who increased the number of Adhans for the Jumua prayers to
three was Uthman bin
Affan and it was when the number of the
(Muslim) people of Medina had increased. In the lifetime of the
Prophet there was only one Mu'adh-dhin and the Adhan used to be
pronounced only after the Imam had taken his seat (i.e. on the
pulpit).
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ
أَبِي سَلَمَةَ الْمَاجِشُونُ، عَنِ الزُّهْرِيِّ، عَنِ السَّائِبِ بْنِ
يَزِيدَ، أَنَّ الَّذِي، زَادَ التَّأْذِينَ الثَّالِثَ يَوْمَ
الْجُمُعَةِ عُثْمَانُ بْنُ عَفَّانَ ـ رضى الله عنه ـ حِينَ كَثُرَ
أَهْلُ الْمَدِينَةِ، وَلَمْ يَكُنْ لِلنَّبِيِّ صلى الله عليه وسلم
مُؤَذِّنٌ غَيْرَ وَاحِدٍ، وَكَانَ التَّأْذِينُ يَوْمَ الْجُمُعَةِ
حِينَ يَجْلِسُ الإِمَامُ، يَعْنِي عَلَى الْمِنْبَرِ.
Sahih Al-Bukhari
But here nafel absolute mean it not sunnah ratimbeh
The Prophet (p.b.u.h) said, "Whoever takes a bath on Friday, purifies
himself as much as he can, then uses his (hair) oil or perfumes
himself with the scent of his house, then proceeds (for the Jumua
prayer) and does not separate two persons sitting together (in the
mosque), then prays as much as (Allah has) written for him and then
remains silent while the Imam is delivering the Khutba, his sins
in-between the present and the last Friday would be forgiven."
حَدَّثَنَا آدَمُ، قَالَ حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، عَنْ سَعِيدٍ
الْمَقْبُرِيِّ، قَالَ أَخْبَرَنِي أَبِي، عَنِ ابْنِ وَدِيعَةَ، عَنْ
سَلْمَانَ الْفَارِسِيِّ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم
" لاَ يَغْتَسِلُ رَجُلٌ يَوْمَ الْجُمُعَةِ، وَيَتَطَهَّرُ مَا
اسْتَطَاعَ مِنْ طُهْرٍ، وَيَدَّهِنُ مِنْ دُهْنِهِ، أَوْ يَمَسُّ مِنْ
طِيبِ بَيْتِهِ ثُمَّ يَخْرُجُ، فَلاَ يُفَرِّقُ بَيْنَ اثْنَيْنِ، ثُمَّ
يُصَلِّي مَا كُتِبَ لَهُ، ثُمَّ يُنْصِتُ إِذَا تَكَلَّمَ الإِمَامُ،
إِلاَّ غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الْجُمُعَةِ الأُخْرَى ".
Sahih Al-Bukhari
And in Fateh Albary said: it's not proved by anything
" وأما سنة الجمعة التي قبلها فلم يثبت فيها شيء " انتهى.
"فتح الباري" (2/410).