Start with the guidance and understand the requirements first.
https://assets.publishing.service.gov.u ... ber_20.pdf
https://assets.publishing.service.gov.u ... gov-uk.pdf
A document checklist will be provided when you complete the AN form online also.
https://visas-immigration.service.gov.u ... onality-an
Assuming you are NOT married to a British Citizen and applying in your own right.
Minimum 12 months on ILR.
You need to meet the 5 year residence requirements.
You need to meet the physical presence in UK at the start of qualifying period requirement.
Good character requirements.
Life in UK, English Test/UK Degree.
2 Referees.
Documents:
Passport(s) including stamps covering 5 years qualifying period.
ILR BRP
Life in UK
English Test/UK Degree
2 Referees.
