When is Istikharah (guidance prayer) Du`a offered, before Tasleem (saying asalamu alikum warahmatu allah wa barakatuh to end the prayer), or after it?
It is offered after Tasleem.
How do I deal with whispers (waswasa) in ablution and purification?
Whispers in ablution are from Satan, and the Muslim should not pay attention to them. He is not required to re-perform ablution or repeat washing a limb because of waswasa. He should always base his purification on its being valid. It is recommended for him to frequently say "La ilaha illa Allah" (There is no god but Allah), because Satan recoils when Allah is mentioned. And Allah the Almighty knows best.
What is the ruling on istinja' after urination, and is it done with water and soap or with water only?
Istinja' from urine and stool is obligatory. It is permissible to perform istinja' with water alone, or with toilet paper alone. The best way is with toilet paper then water. If one wishes to suffice with one of them, then water is better. And Allah the Almighty knows best.
How is Laylat al-Qadr observed?
Laylat al-Qadr is observed through various acts of worship and obedience, including:
● Performing obligatory, Sunnah, and voluntary prayers
● Reciting the Quran
● Increasing remembrance (dhikr) of Allah
● Giving charity
● Performing I‘tikaf
● Inviting others to Allah
It is also Sunnah to increase in supplication and humbly beseeching Him, Glorified and Exalted be He.