The following 5 conditions need to be fulfilled for Hajj al-Qiran to be deemed valid:
1) Performing the Tawaf of Umrah during the months of Hajj (Shawwal, Dhu al-Qadah, and the first nine days of Dhu al-Hijjah). If the Tawaf of Umrah is not performed during this time, Hajj Qiran will not be valid
2) Performing Tawaf of Umrah before the Wuqoof e Arafah (staying in Arafah on the 9th of Dhul Hijjah). If Tawaf of Umrah is performed after the Wuqoof e Arafah, Hajj al-Qiran will not be valid.
3) Putting on Ihram clothes and entering the state of Ihram for Hajj before the Tawaf of Umrah. Therefore, if the Ihram for Hajj is put on after performing Tawaf of Umrah, Hajj Qiran will not be valid.
4) Putting on the Ihram for Hajj before the Umrah becomes invalid. Therefore, if the Ihram for Hajj is put on after the Umrah becomes invalid, Hajj Qiran will not be valid.
5) Ensuring that the Umrah of Hajj al-Qiran does not become invalid. Therefore, refraining from sexual intercourse before performing the Arkan of Umrah, and similarly, refraining from it before wuqoof in Arafah to ensure that Hajj does not become invalid.
To make the intention for Hajj al-Qiran, recite:
"اللھم إني أرید الحج و العمرۃ، فیسرھما لي و تقبلهما مني".
Translation: O Allah! I intend to perform Hajj and Umrah, make them easy for me and accept them from me.
(Adapted with minor modifications from "Anwar Manasik" by Mufti Shabir Ahmad Qasmi Sahib, Damat barakatuhum, published by Maktabah Yusufiyah, Deoband)