wa'alaikumussalam warahmatullahi wabarakatuh
MashaAllah brother Ayman1 and sister Tabassum has answered your questions perfectly.
Know that Islam is the religion of Ease in all its affairs. It does not have any burden on us which we cannot carry. It has one way in most important Fards of it, and has different ways in Nawafils. Why? Because then only it will be easy for us to choose any option that fits into our Iman, Time, Willing Power and Ability.
Let me try to give my answers.
1. is witr prayer only performed after praying tahajjud prayers or can it b performed before them?...is it must to recite dua qunoot or can i recite any other dua?
Witr is the last prayer before Fajr. So we must try our best to make it last. But....
If you have done Witr and went to bed because you were not sure whether you will be able to wake-up later for Tahajjud, then what?
What you need to do is just to pray Tahajjud and DO NOT do another Witr. Because there will be only one Witr in each night.
As per Qunoot, yes you are highly recommended to say Qunoot in Ramdan Witrs. You can read it by holding a paper by your left hand, until you memorise it.
2. how do u pray witr?...is 3 rakaah or 1 rakaah?....if i pray 3 rakaah then in the last rakaah do i need to say Allahu akbar raise my hands like when i start prayer and then recite dua qunoot or any other dua?
In Islam, what I do is not important. But since you asked, let me tell that I do both 3 Rak'ahs and One Rak'ah too. It depends on time and situations.
Short way to perform Witr is 1 Rak'ah. Mid way is 3 Rak'ahs and Long way is 11 Rak'ah. When doing in Mid and Long way, you can perform all the Rak'ahs at once without any Tashahhud and make Tashahhud in the last Rak'ah.
OR
You can do them 2 units by 2 units, making Tashahhud in every 2 unit, and + 1 Rak'ah to finish 11. If 3 Rak'ahs is chosen, then make 2 units, make Tashahhud and + 1 Rak'ah.
I am unaware about saying Takbeer (Allahu Akbar) when raising hands for Qunoot.
3. how many rakaahs are there for dhuhr??....some people pray 4 sunnat , 4 fard and 2 sunnat while others pray 2 sunnat , 2 sunnat , 4 fard , 2 sunnat and 2 sunnat..........so which 1 is rite?....
Zuhur has 4 Fard Rak'ahs. Thats all. We do not call its Sunnah as Duhur. Duhr has 2+2 sunnahs before and 2+2 sunnahs after.
Its is Narrated from rasoolullah (sallallahu 'alaihi wasallam) that if a person keep praying a particular 12 Rak'ahs of Nawafil (named as Highly recommended Rawaatib Sunnahs), after naming them all, Allah (subuhaanahu wata'aala) will build a Palace for Him in Jannah. [Those Sunnahs are, 2 before Fajr, 4 before Duhr, 2 after Duhr, 2 after Maghrib and 2 after Isha].
So you see 2 after and 4 before Duhr is included here. Although someone say its only 2 sunnahs after Duhur or if someone say its 2+2 sunnahs after it, that's not a problem. Both are correct. In both ways, 2 Rak'ahs are there, which is included in that 12 Rak'ahs mentioned in that Hadith.
I posted a thread about this, but I'm still confused on Witr. Can I read Only 1 rakat witr or does it ALWAYS have to be combined with 2 As Shaf rakats?
Hope I have answered this too.
Brother I hoe this helps you, without any confusion. Brother Ayman1's and sister Tabassum's answers are FULLY correct. You choose any option.
wassalam 'alaikum warahmatullahi wabarakatuh