Registering, step by step
The Charity tab lists the steps in order. Some tick themselves from what's already in Trustees: three or more trustees all declared eligible (The board), the constitution re-adopted at an AGM in the last 15 months, last year's accounts approved (the AGM page), and the charity number once it's in Settings.
The rest you tick: your charitable purposes and public benefit written down, a bank account in the charity's name, trustees' details gathered, the application made, the number added to Scouts' membership system, and your District, bank and HMRC told.
Dates of birth stay out of Trustees. The Commission asks for every trustee's date of birth, and HMRC for officials' National Insurance numbers. Trustees never asks for or keeps them: gather them just for the application.