When you visit Adhaar Enrolment center these steps will be followed:
You'll be expected to stand in queue if you've not booked an appointment. My one center in which I enrolled I had to enter my name in queue register at 10am.
You need to fill one page Adhaar enrolment application form and have ready one copy of ID proof and address proofs as well as their originals.
Your both ID proof and address proof will be verified and registered
Your all fingers impressions will be collected
Photograph of your eye iris will be taken
You'll be given an acknowledgement copy containing enrolment number and date/time of application.
Remember all the data will be directly fed into UID computers by Central Government.
Carefully check the details when they are being fed on the computer screen
Please Note
If Adhaar card is registered for you then you'll get it through post at your address. If you don't, then don't worry - first check your Adhaar card status using the enrolment number and date/time of application in the Acknowledgement Slip you've got. Then you can download E-Adhaar online yourself. Just take a print out.