Mufti saheb, can you please tell me what is the manhaj (methodology) of establishing khilafah. On both an individual and collective scale?

Kindly be specific in your question as it is too general.

However, an effort should be made by every Muslim to adhere to the laws of
Shari'ah in every aspect of his/her life. That dedication is a stepping
stone to achieving one's aim of establishing an Islamic state.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai
FATWA DEPT.