Tier1 General dependent applying ILR - process

Hi

I have ILR (which I got after completing 5 years in Tier1 General) got in April-2016.
Now my wife and son (who came in Aug 2013 to UK and their current visa extended in oct 2017 until OCt 2020) as now they completed more than 5 years, I am planning to apply for their ILR.

Please help me in what is the new process (applying online with SET O form?) and what are the documents I need to submit? (I heard that we need to apply all the scanned documents along with online application?)
please suggest.

Also on other note, I am also applying for British citizenship now, will my son gets british citizenship directly without an ILR if I apply for his British citizenship after I receive my british citizenship?

Please help me.

Thanks

The online form will tell you what documents to submit.

A child born abroad requires ILR before they can register as British.

Thanks for your reply and information.
one more question, after my son gets his ILR, do he need to wait for 12 months to apply for his british citizenship? or can he apply immediately after his ILR (assuming only me having british citizenship by that time and my wife on ILR)?

Thanks

He can apply once he has ILR and your are British and the other parent holds ILR.