VA4FA - Online Settlement Application

Hi

I have a question to ask regarding Settlement Applications made online.
http://www.visa4uk.fco.gov.uk/ApplyNow.aspx

Note: - My Spouse is to turn 21 in Early June

Questions

1. When should I start the Online Application.
As I want to apply as early as possible to coincide with her turning 21.

1a. Can I apply from anywhere or will it be where the High Commission is based

2. What is the process of applying? E.g, Application first, then going to appointment, paying for the applications, supplying documents/

Hope anyone can help my confusion, I am going through an information overload.

Other

Hope to receive some replies from people who know the exact process, and how long a gap they got when they applied, so is it days/weeks to supply the next step of info?