Sorry leo, didn't see the second part of your post.
The documents required for your computer number are :
1. Your tenth standard marksheet, passing certificate and verification.
2. Your twelfth standard marksheet, passing certificate, and verification.
3. Proof of Date of Birth (Birth certificate works best here).
4. Address proof.
So just send in the attested photocopies of all these documents plus the printout of the form you have to fill on udaan.nic.in (again, the form needs to be attested) within ten days of the date of submission of the online form.
Please take a look at the guidelines for applying for a computer number on the dgca website before you apply, the process is clearly described there and you should not miss anything as any issue with the application will lead to it being rejected. You can PM me for any other questions, and I will answer them to best of my knowledge. I'm new here so I'm not sure about how strict the rules are about going a off topic.